📅 Original date posted:2017-09-08
📝 Original message:Hi Luca,
Bravissimo!
Please allow me to encourage your to follow the BIP workflow as specified
here
https://github.com/bitcoin/bips/blob/master/bip-0002.mediawiki#BIP_workflow
BIP Editor freely allocates BIP numberss, however that does not constitute
approval but allows for much easier discussion of and communication about
the proposal.
Good luck !
On Wed, Sep 6, 2017 at 9:08 AM Luca Venturini via bitcoin-dev <
bitcoin-dev at lists.linuxfoundation.org> wrote:
> Hi everyone,
>
> I would like to propose a standard protocol to manage tokens on top of
> the Bitcoin blockchain.
>
> The full text is enclosed and can be found here:
>
> https://github.com/token21/token-protocol-specification
>
> Any feedback will be appreciated.
>
> Luca Venturini
>
> ---
>
> Abstract
> ========
> This document describes a protocol to manage digital assets (tokens) on
> top of the bitcoin blockchain. The protocol enables a semantic layer
> that permits reading the bitcoin transactions as operations related to
> tokens.
>
> The protocol allows a new level of plausible deniability, while
> permitting statefull public auditability on each issued token. It allows
> both the user and the issuer to deny that an existing bitcoin
> transaction between the two is actually a token transaction, or a new
> token issuance. While both the token sender and the token issuer cannot
> deny to have sent bitcoins, nobody can prove the transaction was related
> to a digital asset. On top of that, to guarantee plausible deniability,
> tokens can be issued, sent, and received using any existing bitcoin
> client software.
>
> There is no need to have a wallet exclusively dedicated to manage the
> tokens. With a few simple precautions by the user, tokens can be managed
> using any existing Bitcoin wallet, while it is used for normal bitcoin
> transactions as well.
>
> Since it is possible to infinitely split a token in parts, there is no
> definition of the number of decimals of token generated and transferred.
> The number of tokens is always an integer.
>
> Every operation of the protocol is performed with Bitcoin transactions,
> without the use of OP_RETURN and without any form of pollution of the
> blockchain, or of the UTXO set.
>
> The protocol permits atomic buy and sell transactions between tokens and
> Bitcoin, and between different types of tokens. The only operations that
> require a coin selection enabled wallet are the split and join special
> operations and the token offering issuance operations. Those are used to
> modify the token unit of measure and to receive bitcoins from third
> parties during a token offering issuance.
>
> Copyright
> =========
> This document is licensed under the 2-clause BSD license.
>
> Motivation
> ==========
> The current protocols that permit to issue tokens based on the bitcoin
> blockchain (i.e. Counterparty, Omni, Colored Coins, Coinprism, Colu) are
> flawed.
>
> The existing solutions usually need dedicated wallets and/or
> verification nodes. Usually, a "pivot" currency is involved and atomic
> transactions are not permitted unless they use the pivot currency. Those
> protocols pollute the blockchain (30% or more) and in some cases they do
> not accept P2SH scripts. Since the use of a dedicated wallet is
> required, the users cannot plausibly deny they have got tokens.
> Plausible deniability on the issuer side is not available either. None
> of these protocols permits infinite division of the tokens, so usually
> the number of decimals has to be specified at issuance time. The
> automatic token offering issuance is not enabled as well.
>
> Rationale
> =========
> Let's take an example from the real world, a yacht. We write on the
> yacht's license that the owner is any person that can show a one dollar
> bill having the serial number F82119977F. Thus the one dollar bill can
> be exchanged between owners with extreme simplicity and full plausible
> deniability. The US government will guarantee that there is no other
> person having the same dollar bill.
>
> The protocol permits managing a token in the same way. The underlying
> Bitcoin protocol will guarantee against double spending.
>
> Features:
>
> - Easy of use. Tokens can be managed using any wallet. Even if the
> wallet has no coin selection feature.
> - Plausible Deniability by the issuer. The issuer can generate a new
> type of token and nobody analyzing the blockchain will understand that
> the transaction is issuing a token. Even if a token is known, the issuer
> can issue other tokens. Since a single output contains a large number of
> different token types, the issuer is actually generating different types
> of tokens every time she sends a new Bitcoin transaction to the network.
> - Plausible Deniability by the user (no use of tokens at all, or use
> of a different token type). A transaction that sends tokens from Alice
> to Bob is a normal transaction. Nobody can understand that this
> transaction is moving tokens unless they explicitly know which
> transaction is the token issuance. In fact a single address contains a
> large number of token types, and the use of tokens itself can be denied.
> - Accountability. Everybody can see the state of the distribution of a
> type of token.
> - Tunnel mode (confidentiality by issuer and user versus a third
> party). Alice can send tokens to Bob and ask him to give the tokens to
> Charlie, without telling to Bob what is the type of the token given.
> Alice can disclose this information in the future, if she wants.
> - It is possible to perform open or closed issuances. While an open
> issuance permits to continue the issuance of tokens in the future,
> closed issuance guarantees that no other token of the same type will
> ever be issued.
> - The power to continue the issuance of an open token can be sent to
> another address, using a transaction. Once the power to continue the
> issuance is sent to someone, the former issuer cannot issue any more
> tokens.
> - The power to continue the issuance has the same features of
> plausible deniability of the possess of a token.
> - Since a token type is uniquely identified by a transaction hash, or,
> in some cases, by a Bitcoin address, a user can prove to be the issuer
> by signing a message using the Bitcoin protocol.
> - Future proof. Tokens can move following P2PKH, P2SH, P2SH-P2WPKH
> outputs or any other type of script
> - Blockchain pollution of the protocol transactions is almost zero.
> There is no OP_RETURN involved, nor any other type of "fake" addresses
> that pollute the UTXO database.
> - The protocol is based on the Bitcoin blockchain, but, with small
> changes, can be considered blockchain agnostic.
> - Atomic transactions between tokens and Bitcoin are possible.
> - Atomic transactions between different types of tokens are possible.
> - Tokens of different types can be held by the same address and by the
> same output.
> - Tokens can be divided indefintely, thus having any number of decimals.
> - Tokens can be issued automatically on the receiving of bitcoins.
> This operation performs a token offering issuance (also known as Initial
> Coin Offering).
>
> Introduction
> ============
>
> Where are the tokens?
> ---------------------
> As with bitcoins, tokens are contained in unspent Bitcoin outputs. In
> some cases, defined below, the last five digits of the satoshi value
> sent to the output represent the number of tokens contained in the output.
>
> When an output is spent, the tokens contained in the output are fully
> spent in the same transaction. There are no tokens outside of the tokens
> contained in the UTXO database.
>
> Token issuance
> --------------
> The large majority of bitcoin transactions can be semantically seen as
> token issuances. There are two types of token issuances: closed and
> opened. A closed token issuance guarantees that no other token of the
> same type will ever be issued.
>
> Issuance chains
> ---------------
> An open issuance gives to one, or more, of its output the power to
> continue the issuance of tokens of the same type. We define such a power
> as Power of Continuation (POC). The transaction that will spend the
> output appointed with the POC will be a continuation of the same
> issuance chain.
>
> Every transaction of the chain will issue the same type of token. On top
> of that, every transaction that is part of the chain, can also be seen
> as as issuance of tokens of its, new, type. A chain will be closed by a
> transaction having more than one output and the first output with five
> zeros as the last five digits of the satoshis value. No other
> transactions can send tokens of the same type after the close of the
> issuance.
>
> Token names
> -----------
> A token type can have multiple names. The default name is the hash of
> the first transaction that issued the token.
>
> i.e: 68330b6ab26e44f9c3e515f04d15ffe6547f29e60b809a47e50d9abf59045c1e
>
> As alternative names, a token type can be named after the bitcoin
> address of one of the outputs of the transaction that first issued the
> token, provided the fact that the address has never been used before in
> the blockchain.
>
> Note: it is better to use one of the alternate names in cases when
> transaction malleability is a concern.
>
> Vanity token names
> ------------------
> A token can be identified using only the first characters of the Bitcoin
> address, as alternate name defined above, if the characters are
> different from every previous Bitcoin address seen in the blockchain. An
> example is provided below.
>
> Tokens can coexist
> -------------------
> Token of different types can coexist in a single output while remaining
> of different types. Thus a bitcoin address (actually an output of the
> UTXO database) can hold tokens of different types. Every Bitcoin address
> contains a lot of types of tokens, so that a user usually does not know
> all the type of tokens contained in an address.
>
> A single transaction can send a type of token to some of the outputs
> while sending another type of token to a different set of its outputs.
> Tokens are never burned or deleted.
>
> Use the protocol
> ================
> This section explains a basic use case. In all the examples provided, we
> do not consider the fee. We assume that there is another input, not
> listed, that pays the transaction fee.
>
> Alice, Bob, Charlie, and Daniel decides that they want to start a new
> company. Each of them will give to the new company some time, money,
> furniture, knowledge. They decide everyone contributed to the company
> with a percentage of value as follows: Alice - 40%, Bob - 12%, Charlie -
> 34% and Daniel - 14%. They decide that the shares of the new company can
> be freely resold to others and that they will accept that the annual
> meeting will consent vote through messages signed using the Bitcoin
> protocol by the owners of the shares.
>
> Issue tokens
> ------------
> Alice asks Bob, Charlie, and Daniel to send her 1 Bitcoin each. She asks
> each of them to give her a bitcoin address where they want to receive
> back the bitcoins along with the tokens.
>
> She asks Charlie to generate a vanity address that has never been used
> before of type 1CompanyXWXjLgud9jxwxm34u.... Since there has been a
> previous address in the blockchain having 1Companx as the first
> characters, but this is the first address seen in the blockchain that
> has 1Company as the first characters, they will call the token with the
> name 1Company. This step is optional.
>
> Then she sends, from her wallet, a transaction having the following
> outputs:
>
> - 1.00000040 to an address controlled by Alice
> - 1.00000012 to an address controlled by Bob
> - 1.00000034 to the vanity address 1CompanyXWXjLgud9jxwxm34u...
> controlled by Charlie
> - 1.00000014 to an address controlled by Daniel
> - 3.45322112 is the change generated by Alice's wallet
>
> This transaction gives 40, 12, 34, 14 tokens to each one. The newly
> generated token type can be named after the transaction hash, or after
> the vanity address (optional), or after one of the addresses of the
> persons involved, provided that the address has never been used before.
>
> The issuance is still open. Since they do not want to issue more shares,
> they decide to close the issuance (on the other side, they could decide
> to leave the issuance open and to hold the issuing key somewhere, or to
> have a multisignature address and to give the keys to the directors of
> the company). In order to close the issuance, Alice generates the
> following transaction that sends bitcoins from her wallet to addresses
> of her same wallet, using the change output of the previous transaction
> as an input:
>
> - 0.45000000 to an address of her wallet
> - 3.00322112 change generated by the wallet
>
> This closes the issuance.
>
> Send tokens
> --------------
> After some while, Bob decides to give some shares of the company to his
> husband Giacomo. He generates a new transaction spending the output of
> the issuance transaction:
>
> - 0.03400008 to Giacomo
> - 0.96600004 change generated by Bob's wallet
>
> This transaction gives to Giacomo 8 shares of the company.
>
> Atomic transactions
> -------------------
> Daniel wants to sell 3 of his 14 shares to Frank. They negotiate a price
> of 0.00323200 bitcoin per share. This is a total of 0.00969600 bitcoin
> to buy the three shares. They do not know each other very well, so they
> decide to make an atomic transaction that will give 0.00969600 bitcoins
> to Daniel and 3 shares to Frank. Daniel set an input of the new
> transaction with his issuance transaction output. Frank put in another
> input of 1.23242454 bitcoins from his wallet. The outputs of the
> transaction are as follows:
>
> - 0.22400003 to an address controlled by Frank (this gives the 3
> shares to Frank)
> - 0.23200000 to an address controlled by Daniel (this is part of the
> payment to Daniel)
> - 0.77769614 to an address controlled by Daniel (this can be
> considered the change of the original issuance output of 1.00000014)
> - 0.99872851 to an address controlled by Frank (change to Frank)
>
> Daniel sent to the inputs of the transaction 1.00000014 bitcoins and
> receives back 1.00969614. This gives to Daniel the 0.00969600 paid by
> Frank. On the other side, Frank sends 1.23242454 as an input of the
> transaction and receives back 1.22272854 bitcoins, thus paying exactly
> the 0.00969600 that needs to be paid to Daniel. This transaction sends 3
> tokens from Daniel to Frank. Another 11 tokens are the tokens that are
> given as a change to Daniel, along with 0.23200000 bitcoins.
>
> Specification
> =============
>
> Definitions
> -----------
> In order to evaluate a transaction, the outputs are sorted by the
> satoshis value. Once sorted, we define a "cut" output the first output
> having five zeros as the last five digits of the satoshi value (satoshis
> modulo 10^5 == 0). In the following, "first", "second", "last" are all
> referred to the sorted outputs.
>
> We define as "signal" of an output the value of satoshis of the output
> modulo 10^5. This is the last five digits of the value, as expressed in
> satoshis.
>
> Despite not mandatory, we sometimes call "c", or "change", the output
> having the biggest value in Satoshi. This is the last output, as sorted
> above. Such behavior follows the "Guidelines" section, explained below.
>
> We use n=0 related to a sequence a1, ..., an, to indicate that there are
> no elements in the sequence.
>
> Issuance of a token
> -------------------
> A transaction that has only one output, or has the first output that is
> a cut, issues no token. Every other Bitcoin transaction is an issuance
> of tokens of the type of the transaction.
>
> When a issuance is open, Power of Continuation (POC), will be given to
> an output that will be spent in a transaction that continues the
> issuance of the same type of tokens.
>
> As for the protocol behavior, we divide the structure of the sorted
> outputs of a bitcoin transaction in the following groups. For each
> group, a description of the behavior of the protocol is provided.
>
> - a1, ..., an, cut(POC), z1(POC), ... zm(POC), b1, ..., bl, with n>0,
> m>=0, m+l>0
> * zi are outputs signaling zero. They are optional.
> * This is an open issuance. It generates the number of tokens
> signaled by the outputs before the cut: a1, ..., an. Every output of
> that set receives a number of tokens as signaled by the output satoshis'
> value.
> * The cut output, and every other output zi, signaling zero, that
> is directly after the cut, receive the POC. This means that the
> transactions that will spend the POC will be a continuation of this
> issuance and a continuation of every issuance that gave the POC to the
> this transaction.
> - cut, b1, ..., bm with m>0 (a cut alone is a case of the fourth type)
> * This is a particular case of the first group, having n=0 and
> m=0. This transaction *closes the issuance forever*. Every token's chain
> that ends into this transaction is closed as well.
> * It generates no tokens and there are no other outputs that can
> continue the issuance in the future.
> * If b1 or b2 have a signal of zero and m>2, this is a token
> offering issuance transaction. It will be described in a following section.
> - a1, ..., an, c(POC) with n>0
> * This is an open issuance. It generates the number of tokens that
> are signaled in a1, ..., an. The last output c will not receive tokens.
> * The last output c will receive the POC. A following transaction
> that spends the output c is an issuance transaction of the same type of
> token.
> * The fact that c is a cut (or not) does not modify the behavior
> of the transactions of this group
> - c(POC) (single output, also seen as the previous one, with n=0)
> * This transaction generates no tokens at all.
> * The output c receives the POC. Thus a following transaction that
> spends the output c is an issuance transaction of the same type of token.
>
> Notes on token issuances
> ------------------------
> The number of tokens generated by an issuance transaction is always the
> sum of the signals of all the outputs, excluding the last one and the
> outputs that are listed after a cut. Thus the number of tokens sent to
> each output, that receives tokens, is always the number signaled by the
> output.
>
> Who has the power to generate other tokens of the same issuance (POC):
>
> - If there is no cut, the issuance is open and the transaction that
> will spend the last (biggest) output can continue to generate token of
> the same type.
> - If there is a cut, in a position different than the first, the
> issuance is open. The cut output will be the input of a following
> transaction that issues more tokens of the same issuance chain. The
> following transaction can close tha chain, or can be an open issuance,
> thus having another output that will continue the generation chain.
>
> In order to close forever the issuance of tokens, the transaction should
> have a cut as the first output and have more than one output.
>
> Transfer of tokens
> ------------------
> Every bitcoin transaction spends all the tokens' content of the inputs
> and sends them to the outputs. Some of the outputs receive the number of
> tokens exactly stated in the last five digits of the satoshis sent (the
> signal), in a way similar to an issuance transaction.
>
> A transaction can be seen as having one of the three following shapes
> (ai means an output that is not a cut, bi and c are outputs that can be
> cut):
>
> - a1, ..., an, cut, b1, ..., bm, c (transactions with a cut) (n=0 is
> described here)
> * No output (bi) after a cut receives tokens.
> * Tokens will be assigned to outputs a1, ..., an trying to follow
> the signal as follows:
> - If there are enough tokens, the tokens signaled by the first
> output are assigned to that output.
> - If there are still remaining tokens, the tokens are sent to
> the following output based on the signal.
> - This continues until there is a cut or the tokens signaled
> by an output are more than the remaining tokens. In these cases:
> * If there is a cut, it receives all the remaining tokens.
> * If there is an output receiving more tokens than the
> remaining tokens (we define it a "remaining error"), the output receives
> no token at all. No other output will receive tokens after this and all
> the remaining tokens will be sent to the last output c (thus, if there
> is a cut in the transaction, the algorithm "jumps" the cut).
> * If there is a "remaining error" and the transaction is a
> special transaction as defined in the next section, and the number of
> tokens in input is exactly the same of the two types (big and small)
> that are the result of a previous split or join special transaction, the
> "remaining error" output gets one of the smallest tokens involved. This
> will be better explained in the following section about "special
> transactions".
> * If the first output is a cut, and the transaction is not a
> special one as defined below in the document, the last output (c)
> receives all the tokens
> - a1, ..., an, c (ai is not a cut, for every i; c can be a cut)
> * The tokens are assigned to a1, ..., an as described in the
> previous group.
> * The last output c receives all the remaining tokens. This
> behavior is not modified by the fact that the last output is a cut.
> - c (single output transaction, also seen as the previous one, with n=0)
> * The output receives all the tokens received from the inputs
>
> Transactions receiving both the POC of an issuance and some tokens of
> the same issuance
>
> ---------------------------------------------------------------------------------------
> The protocol is designed such that a transaction of an issuance chain
> never issue new tokens to an output, that receives the POC of the same
> type of token. But two different inputs can give to a transaction both
> some tokens and the POC of the same type of token. In this case, there
> is a double role for the transaction that is both a continuation of the
> issuance and a transfer transaction sending tokens of the same type.
>
> In this case, the tokens will be allocated as defined in the following
> four different shapes of transaction:
>
> - a1, ..., an, cut, b1, ..., bm, c (transaction with a cut)
> * The generated tokens are sent to the outputs a1, ..., an as
> described in the definition of an issuance of tokens
> * All the tokens received in input of the same type of the
> issuance we are continuing will be sent to the cut output
> - a1, ..., an, c (transaction without a cut, or with c that is a cut:
> ai is not a cut, for every i)
> * The generated tokens are sent to the outputs a1, ..., an as
> described in the definition of an issuance of tokens transaction
> * All the tokens received in input, of the same type of the
> issuance we are continuing, will be sent to the last output c
> - cut, b1, ..., bm
> * The issuance will be closed and all the tokens will be given to
> the last output bm. The behavior described in the issuance transaction
> and in the transaction sending tokens do not influence each other, in
> this case.
> * If it is a special transaction, as defined below, there is no
> overlap between the definitions. The issuance chain is closed and the
> received tokens will be given as defined.
> - c only
> * The definitions of issuance transaction and transfer transaction
> can be used. The issuance will remain open and the address will receive
> all the tokens received from the inputs
>
> Since both the first and the second group of transactions are giving the
> POC to the same output that receives the tokens, the output will
> continue to carry both the tokens received and the POC. This delegates
> someone to issue new tokens and allocates some tokens from a previous
> issuance that are still not assigned.
>
> Split and join transactions
> ---------------------------
> A split or join transaction is one that has one of the following formats
> of outputs:
>
> - cut, a1, ..., an, z, b1, ..., bm (z is an output signaling zero,
> like a cut)
> - cut, a1, ..., an, c
>
> having the added condition that the sum of the signals of the outputs
> a1, ..., an is:
>
> - equal to the number of tokens received in input divided by 1000 (we
> call it a join transaction), or
> - equal to the number of tokens received in input multiplied by 1000
> (we call it a split transaction)
>
> Since the presence of these two extra conditions, the fact that a
> transaction is a join or split transaction, or it is not (hence it is a
> simple transfer transaction), depends on the number of tokens received
> in the input. A given transaction can be both split or join for some
> type of tokens, and normal for other types of tokens.
>
> Note: this is the same format that closes an issuance chain. If the
> transaction receives both POC and tokens of the same type, the
> transaction chain will be closed and the received tokens will be sent as
> described here.
>
> Note: this is also the format of a transfer transaction that assigns to
> the change c or bm, the token received in the input. But, if a
> transaction is a special one of the first two types, that behavior
> should not be considered and no tokens will be transferred to the change.
>
> The split transaction generates a new type of tokens with a value that
> is one thousandth of the value of the type of tokens received in the
> input. This new type can be mixed with tokens generated by other similar
> split transactions, based on the same original token. Split tokens have
> the same value and can be joined in the future with join transactions.
>
> The join transaction generates a new type of tokens with one thousand
> times the value of the type of tokens received in the input. This new
> type of token can coexist with tokens generated by other similar join
> transactions, based on the same original token. Joined tokens from the
> same original token, have the same value and can be split in the future
> with split transactions. Thus becoming again original tokens.
>
> In a special transaction of the second group, without "the second cut"
> z, the change is mandatory and does not receive tokens. This means that
> the number of tokens sent is summed up without the last output. If the
> number is not correct, then it is not a split or join transaction.
>
> Tokens split or joined are of a different type than their original
> source. This means that they can coexist in the same output and will
> never mix together. Thus a output having 3 big tokens and 456 tokens
> obtained by a split transaction, seems to have 3.456 tokens, but, in
> fact, has 3 tokens of a type and 456 tokens of another type (the second
> type is referred as the original type with a 0.001 unit of measure).
>
> Note: as described below, there is a procedure of separating tokens of
> different types contained in the same output. This procedure will not
> work if the two type of tokens are present in the same output in the
> same number. Thus if an output contains exactly 3.003 tokens (3 big and
> 3 small), the tokens cannot be separated anymore. This is why we
> introduced, in the transfer transaction definition, the rule that
> assigns in this case one single token of the smallest type to the
> "remaining error" output.
>
> Token offering issuance transactions
> ------------------------------------
> A token offering issuance transaction is a transaction having one of the
> following formats (z is an output signaling zero, like a cut; r and s
> are outputs that signal a value greater than zero; the group of outputs
> (t1, t2, z) is optional; t1 or t2 can signal zero, but not both):
>
> - cut, z, r, (t1, t2, z,) a1, ..., an, c
> * price of tokens are predefined
> - cut, s, z, (t1, t2, z,) a1, ..., an, c
> * price of tokens are not predefined
>
> The tokens will be assigned to one of the outputs of every transaction
> that sends bitcoin to the address of the outputs r or s, as follows:
> - if the sending transaction has only two outputs (r, c), (c, r), (s,
> c) or (c, s), the "other" output c receives the tokens.
> - if the sending transaction has more than two outputs, the last
> (biggest) output that is not the one sending bitcoins to r or s, will
> receive the tokens.
> - if the sending transaction has only one output, the generated tokens
> will be assigned to the output r or s itself. This can be considered as
> a donation: it generates tokens, but the tokens remain in the
> availability of the issuer.
> - since the number of token emitted is always an integer, the
> remaining satoshis are not considered in the number of tokens issued and
> are sent to the issuer without any token generation.
>
> Note: this is the second place, in this document, where the bitcoin
> address of an output is used. The other place regards the alternate
> names of an issuance. Everything else in the protocol is based on
> outputs, not addresses.
>
> If the group (t1, t2, z) is present, it signals how many token will be
> issued. The total number of tokens that will be issued is the number
> signaled by t1 * 10^6 + the number signaled by t2. In any block, the
> issuance can be closed by the transaction that spends the outputs r or s.
>
> Timeline:
> - The offer starts in the block that contains the token offering
> issuance transaction. Every transaction of the starting block receives
> tokens, without order.
> - If there is a defined total number of tokens, the issuance will end
> when the total number of tokens has been reached.
> * Inside the last block, the transactions are considered in the
> order they are listed. So if a transaction takes the last tokens, every
> other transaction sending bitcoins to r or s, do not receive tokens.
> - The transaction that spends the outputs r or s ends the issuance.
> This transaction suspends the issuance even if a defined number of
> tokens was defined in the token offering issuance transaction.
> * In case of an issuance suspeded, or ended, by a transaction
> spending r or s, every transaction of the block containing the spending
> transaction will be considered valid as a receiver of tokens.
> * Thus, sending bitcoins to the address of the outputs r or s will
> be considered as part of the offering, only if it is included in a block
> between the block of the transaction that has r or s as an output
> (start), and the block of the transaction that spends the output r or s
> (end), inclusive.
>
> A token offering issuance transaction of the first type permits to set a
> rate, and to issue tokens every time bitcoins are received by an
> address. The rate is defined by the number signaled by the output r. One
> token will be issued for every r satoshis received.
>
> A token offering issuance transaction of the second type does not set a
> predefined rate at the start. The rate will be defined by the
> transaction that closes the issuance by spending the output s. The first
> (smallest) output of the closing transaction, or the first output after
> the cut (if a cut is present), will signal the rate. This type of token
> offering issuance, having the price defined at the end, permits to issue
> token based on parameters related to the issuance itself. This is the
> case, for example, of Dutch Auctions.
>
> Note: A token offering issuance transaction can be seen as a transfer
> transaction, that sends all the tokens that receives to the output c.
>
> Note: the type of token issued is defined by the token offering issuance
> transaction, seen as an issuance transaction. Since a token offering
> transaction is also the closure of some issuing chains, this means that
> the same token offer will issue different type of tokens. In fact, a
> different type of token will be issued for every issuance chain that
> ends with the same token offering issuance transaction. Thus a token
> type can be first issued in a controlled way (this is usually called
> pre-ICO) and then the rate can be stated, and the same type of token can
> be offered to the public (this is usually called the ICO). Since the
> token offering issuance transaction closes the issuance forever, there
> is the guarantee that no other tokens of the same type will ever be
> issued after the offer is closed. In order to offer tokens at different
> prices, multiple issuance transactions can be generated with POCs
> originating from the same issuance chain.
>
> Atomic transactions between bitcoins and tokens
> -----------------------------------------------
> Using the cut signal and software that allows full "coin selection",
> it's possible to make atomic exchange transactions. The outputs before
> the cut will determine who will receive the tokens and the following
> outputs will define the rest of the transaction. Both the changes (the
> one of the token wallet and the one of the Bitcoin wallet), should be in
> the second set (after the cut). Since the cut will receive the remaining
> tokens, it is suggested that the cut is sent to the seller of tokens.
> Using this method, the remaining tokens can be sent without involving a
> calculation of the remaining tokens. The outputs of an atomic exchange
> transaction will have the following format (seller is the token seller,
> buyer is the token buyer).
>
> - a1: tokens sent from the seller to the buyer
> - a2: tokens sent from the seller to the buyer
> - cut: part of the bitcoin payment sent from buyer to seller
> - b1: part of the bitcoin payment sent from buyer to seller (or change
> sent from seller to buyer, if the price to be paid is less than the
> value of the cut)
> - b2: Bitcoin change sent to the token wallet
> - b3: Bitcoin change sent to the bitcoin wallet
>
> It is impossible to make an atomic exchange transaction if the wallet in
> use does not allow coin selection.
>
> Cross token atomic transactions
> -------------------------------
> Let's say that Alice wants to sell a number x of tokens of type Ta and
> Bob wants to pay using y tokens of type Tb. Token of type Tb are of
> lesser value than the tokens of type Ta, so Bob will pay more Tb tokens
> and Alice will pay fewer Ta tokens (x < y). Let's say that the
> transaction spends an output from Alice containing BTCa bitcoins and
> *exactly* x tokens, while Bob sends to the same transaction BTCb
> bitcoins and a number z of tokens of type Tb. Since z > y, Bob will
> receive a change c in tokens of type Tb.
>
> Alice managed the previous transactions so that a fixed number x of
> tokens can be sent as the input with a number BTCa of bitcoins. Bob is
> not required do the same, because there is the cut that gives the
> remaining tokens back to Bob. In order to simplify let's say that there
> is another input giving the fee for the transaction and the Bitcoin
> assigned to each output will be calculated accordingly.
>
> The atomic transaction can be made by signaling with the first output
> the number y of tokens that Bob should pay to Alice. This output will go
> to Alice. Since y is higher than x, all the x tokens of type Ta will go
> to the change (directed to Bob), while the y tokens of type Tb will go
> to the first output. A following cut can be used to send the change to
> Bob. The addresses following the cut can be used as changes of bitcoins.
>
> The inputs of the transaction will have a content in Bitcoin and tokens
> as follows:
>
> - Alice will spend an output having BTCa bitcoins and containing
> *exactly* x tokens of type Ta
> - Bob will spend an output having BTCb bitcoins and containing y + c
> tokens of type Tb
>
> The outputs of the transaction will have the following form:
>
> - Bitcoin sent: BTCa1; Signal sent: y; Directed to Alice (the output
> gets y tokens of type Tb, but does not get any token of type Ta, because
> x < y)
> - Bitcoin sent: BTCb1; Signal sent: cut; Directed to Bob (no token of
> type Ta given, but receives c tokens of type Tb)
> - Bitcoin sent: BTCa - BTCa1; Signal sent: not important; Directed to
> Alice (no token sent, but useful to send a change in Bitcoin to Alice,
> if needed)
> - Bitcoin sent: BTCb - BTCb1; Signal sent: not important; Directed to
> Bob (this output gets number x tokens of type Ta)
>
> Cross token atomic transactions in the case of the same number of tokens
> to be exchanged
>
> ----------------------------------------------------------------------------------------
> The atomic transactions described above do not work if the value of
> tokens of type Ta is equal to the value of tokens of type Tb. In this
> case, there is no way of doing an atomic exchange.
>
> Let's say that we need to do a transaction between two tokens that have
> the same value: TetherA and TetherB. Let's say that Alice and Bob want
> to change 199 tokens. The atomic transaction cannot be made, but, with a
> small risk, two transactions can be made. The first will be an atomic
> transaction giving 100 tokens of type TetherA from Alice to Bob and
> receiving 99 of type TetherB back, and the second will be 99 to 100.
>
> How to separate different types of token
> ----------------------------------------
> Let's say that an output contains two different types of tokens of
> interest to the user. Is there a way to separate the tokens so that they
> can be sent to different outputs? If the tokens are exactly the same
> number, there is not. If the tokens are two different numbers: x tokens
> of type A and y tokens of type B, then the separation can be done. Since
> the "remaining error" of an output goes to the change, we can send the
> higher value of the two and have the change receive the lower. We assume
> that x < y.
>
> Let's call A1 the output that will receive A and B1 the output that will
> receive the tokens of type B.
>
> The transaction will be similar to the cross token atomic transaction:
>
> - Signal sent: x (the output gets x tokens of type B, but does not get
> any token of type A, because x < y)
> - Signal sent: cut (no token of type A given, but receives a change in
> token of type B if the previous signal was less than y)
> - Other outputs
> - Signal sent: not important (this output gets number x tokens of type A)
>
> Guidelines
> ==========
> There are some suggestions that, if followed by the user, permit
> managing tokens in a simple manner, without technical knowledge of the
> rest of the protocol, with plausible deniability. This can be done using
> any existing wallet.
>
> The guidelines described here are based on a wallet that will be
> "consolidated". This means that all the outputs of the wallet are linked
> toghether. In some cases, this behavior diminish the level of privacy of
> the user. Thus, it is advised to use a number of different wallets, in
> order to reach the desired level of privacy.
>
> Plausible deniability: how to use a wallet to manage tokens
> -----------------------------------------------------------
> Some of the protocol's operations are designed to be managed using a
> coin selection software, however, any wallet without coin selection can
> be used to generate, send, or receive tokens. The option to use any
> existing Bitcoin wallet is the base of the plausible deniability of the
> protocol. The user can send, receive and generate tokens by using any
> wallet in a way that seems a normal use of the Bitcoin protocol to
> manage bitcoins.
>
> Thus, the guidelines in this section are based on a use of a wallet by a
> user without involving any "coin selection".
>
> In order to send or generate tokens, the user needs to have, at any
> time, only one output in the wallet. Let's call it a "consolidated"
> wallet. In order to consolidate a wallet:
>
> - Send all the bitcoins contained in the wallet to a new address of
> the same wallet
>
> If the user departs from these guidelines by mistake, he can "fix" his
> wallet and re-consolidate it without losing the tokens contained in the
> wallet. If the wallet is consolidated, it remains consolidated while
> tokens are generated or sent, and while bitcoins from the wallet are
> spent. If bitcoins or tokens are received by any address of the wallet,
> then the wallet needs to be consolidated again.
>
> Issuance of tokens
> ------------------
> In order to generate tokens:
>
> - Consolidate the wallet if it is not already consolidated.
> - Send a minority of the bitcoins contained in the wallet to a new
> address (outside of the wallet). The last five digits of the satoshis
> sent are the number of tokens generated.
> - From the same wallet, other tokens can be generated by sending again
> a number of satoshis, having the last five digits that are the number of
> tokens to issue to the new address.
> - The value of bitcoins sent should always be less than the bitcoin
> that remains in the wallet
> - If during the process of generating tokens the wallet receives
> bitcoins, it should be consolidated again before continuing to generate
> tokens.
> - The type (or name) of tokens will be the txid of the transaction. If
> the transaction sends bitcoin to a new, never used, address, the address
> can be used as the name of the tokens, as well.
>
> In order to give the power to generate new tokens to another person:
>
> - Send all the Bitcoin content of the wallet to the other person, with
> a single transaction
>
> In order to close an issuance:
>
> - To close the issuance and guarantee that no other tokens of this
> type will ever be generated again, send to another address of the same
> wallet a number of bitcoins with the last five digits of the satoshis
> that is zero. Be aware that this shouldn't be all the content of the
> wallet. If all the content of the wallet is sent to some address, the
> issuance will not be closed. Instead, this gives to the receiver the
> power to generate new tokens.
>
> Spending bitcoins and not tokens
> --------------------------------
> In order to spend bitcoins from the wallet without sending any tokens,
> the user should spend less than half of the bitcoin value contained in
> the wallet, and:
>
> - Spend a number of satoshis where the last five digits are all zeros,
> or
> - Spend a number of satoshis where the last five digits are a number
> greater than the tokens that are in the wallet,
>
> Transfer of tokens
> ------------------
> In order to send tokens to another person:
>
> - Consolidate the wallet if it is not already consolidated.
> - Send a value less than half of the content of the wallet and having
> the number of satoshis where the last five digits are the number of
> tokens that need to be transferred,
> or
> - Send all the bitcoins of the wallet (even if the wallet is not
> consolidated).
>
> If the user sends all the content of the wallet to a single address (no
> change), then he's emptying the token content from the wallet, as well.
> All the tokens will go to the address and nothing will remain to the user.
>
> In order to receive tokens from other users:
>
> - Give to the other person a Bitcoin address of the wallet and ask to
> send tokens as explained above.
> - If the wallet was empty before of receiving tokens, then it is
> already consolidated. Instead, if the wallet already had some bitcoins,
> then the wallet needs to be consolidated before sending or generating
> tokens.
>
> Effects of the use of these guidelines
> --------------------------------------
> When using the guidelines, the number of tokens sent to the recipient is
> always stated in the last five digits of the satoshis sent. There are
> three exceptions:
>
> - In a single output transaction, all the tokens of the wallet will be
> sent to the recipient.
> - In a transaction where the amount of satoshis sent ends with five
> zeros, no tokens are sent.
> - In a transaction sending more tokens than the number of tokens of
> that type held in the wallet, no tokens are sent.
>
> Technical notes
> ---------------
> - Sending a number of bitcoins that is greater than half of the
> bitcoins contained in the wallet brings to unpredicted results.
> - Thus, if there are not enough bitcoins to continue to operate, the
> wallet needs to be "re-charged" by sending some bitcoins to it. By doing
> so, there will be more than one UTXO in the wallet. This departs from
> "consolidated mode" and the wallet needs to be consolidated again.
> - A consolidated wallet contains only one UTXO.
> - Every transaction made from a consolidated wallet contains only two
> outputs: one is the address outside of the wallet, and the other is the
> change.
> - Every transaction spends all the content of the wallet.
>
> Reference Implementation
> ========================
> A reference implementation will be included when the protocol will be
> reviewed and accepted by the community.
> _______________________________________________
> bitcoin-dev mailing list
> bitcoin-dev at lists.linuxfoundation.org
> https://lists.linuxfoundation.org/mailman/listinfo/bitcoin-dev
>
--
Alex Kravets
@alexkravets <https://twitter.com/alexkravets>;
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Alex Kravets [ARCHIVE] /
npub15t…4eg6q
2023-06-07 18:05:29
in reply to nevent1q…ms32
Author Public Key
npub15te7jlfhpkequ3fk7uhwgw700y5ykn6x4llt68y09mejjvn7zfcqs4eg6qPublished at
2023-06-07 18:05:29Event JSON
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"content": "📅 Original date posted:2017-09-08\n📝 Original message:Hi Luca,\n\nBravissimo!\n\nPlease allow me to encourage your to follow the BIP workflow as specified\nhere\nhttps://github.com/bitcoin/bips/blob/master/bip-0002.mediawiki#BIP_workflow\n\nBIP Editor freely allocates BIP numberss, however that does not constitute\napproval but allows for much easier discussion of and communication about\nthe proposal.\n\nGood luck !\n\n\nOn Wed, Sep 6, 2017 at 9:08 AM Luca Venturini via bitcoin-dev \u003c\nbitcoin-dev at lists.linuxfoundation.org\u003e wrote:\n\n\u003e Hi everyone,\n\u003e\n\u003e I would like to propose a standard protocol to manage tokens on top of\n\u003e the Bitcoin blockchain.\n\u003e\n\u003e The full text is enclosed and can be found here:\n\u003e\n\u003e https://github.com/token21/token-protocol-specification\n\u003e\n\u003e Any feedback will be appreciated.\n\u003e\n\u003e Luca Venturini\n\u003e\n\u003e ---\n\u003e\n\u003e Abstract\n\u003e ========\n\u003e This document describes a protocol to manage digital assets (tokens) on\n\u003e top of the bitcoin blockchain. The protocol enables a semantic layer\n\u003e that permits reading the bitcoin transactions as operations related to\n\u003e tokens.\n\u003e\n\u003e The protocol allows a new level of plausible deniability, while\n\u003e permitting statefull public auditability on each issued token. It allows\n\u003e both the user and the issuer to deny that an existing bitcoin\n\u003e transaction between the two is actually a token transaction, or a new\n\u003e token issuance. While both the token sender and the token issuer cannot\n\u003e deny to have sent bitcoins, nobody can prove the transaction was related\n\u003e to a digital asset. On top of that, to guarantee plausible deniability,\n\u003e tokens can be issued, sent, and received using any existing bitcoin\n\u003e client software.\n\u003e\n\u003e There is no need to have a wallet exclusively dedicated to manage the\n\u003e tokens. With a few simple precautions by the user, tokens can be managed\n\u003e using any existing Bitcoin wallet, while it is used for normal bitcoin\n\u003e transactions as well.\n\u003e\n\u003e Since it is possible to infinitely split a token in parts, there is no\n\u003e definition of the number of decimals of token generated and transferred.\n\u003e The number of tokens is always an integer.\n\u003e\n\u003e Every operation of the protocol is performed with Bitcoin transactions,\n\u003e without the use of OP_RETURN and without any form of pollution of the\n\u003e blockchain, or of the UTXO set.\n\u003e\n\u003e The protocol permits atomic buy and sell transactions between tokens and\n\u003e Bitcoin, and between different types of tokens. The only operations that\n\u003e require a coin selection enabled wallet are the split and join special\n\u003e operations and the token offering issuance operations. Those are used to\n\u003e modify the token unit of measure and to receive bitcoins from third\n\u003e parties during a token offering issuance.\n\u003e\n\u003e Copyright\n\u003e =========\n\u003e This document is licensed under the 2-clause BSD license.\n\u003e\n\u003e Motivation\n\u003e ==========\n\u003e The current protocols that permit to issue tokens based on the bitcoin\n\u003e blockchain (i.e. Counterparty, Omni, Colored Coins, Coinprism, Colu) are\n\u003e flawed.\n\u003e\n\u003e The existing solutions usually need dedicated wallets and/or\n\u003e verification nodes. Usually, a \"pivot\" currency is involved and atomic\n\u003e transactions are not permitted unless they use the pivot currency. Those\n\u003e protocols pollute the blockchain (30% or more) and in some cases they do\n\u003e not accept P2SH scripts. Since the use of a dedicated wallet is\n\u003e required, the users cannot plausibly deny they have got tokens.\n\u003e Plausible deniability on the issuer side is not available either. None\n\u003e of these protocols permits infinite division of the tokens, so usually\n\u003e the number of decimals has to be specified at issuance time. The\n\u003e automatic token offering issuance is not enabled as well.\n\u003e\n\u003e Rationale\n\u003e =========\n\u003e Let's take an example from the real world, a yacht. We write on the\n\u003e yacht's license that the owner is any person that can show a one dollar\n\u003e bill having the serial number F82119977F. Thus the one dollar bill can\n\u003e be exchanged between owners with extreme simplicity and full plausible\n\u003e deniability. The US government will guarantee that there is no other\n\u003e person having the same dollar bill.\n\u003e\n\u003e The protocol permits managing a token in the same way. The underlying\n\u003e Bitcoin protocol will guarantee against double spending.\n\u003e\n\u003e Features:\n\u003e\n\u003e - Easy of use. Tokens can be managed using any wallet. Even if the\n\u003e wallet has no coin selection feature.\n\u003e - Plausible Deniability by the issuer. The issuer can generate a new\n\u003e type of token and nobody analyzing the blockchain will understand that\n\u003e the transaction is issuing a token. Even if a token is known, the issuer\n\u003e can issue other tokens. Since a single output contains a large number of\n\u003e different token types, the issuer is actually generating different types\n\u003e of tokens every time she sends a new Bitcoin transaction to the network.\n\u003e - Plausible Deniability by the user (no use of tokens at all, or use\n\u003e of a different token type). A transaction that sends tokens from Alice\n\u003e to Bob is a normal transaction. Nobody can understand that this\n\u003e transaction is moving tokens unless they explicitly know which\n\u003e transaction is the token issuance. In fact a single address contains a\n\u003e large number of token types, and the use of tokens itself can be denied.\n\u003e - Accountability. Everybody can see the state of the distribution of a\n\u003e type of token.\n\u003e - Tunnel mode (confidentiality by issuer and user versus a third\n\u003e party). Alice can send tokens to Bob and ask him to give the tokens to\n\u003e Charlie, without telling to Bob what is the type of the token given.\n\u003e Alice can disclose this information in the future, if she wants.\n\u003e - It is possible to perform open or closed issuances. While an open\n\u003e issuance permits to continue the issuance of tokens in the future,\n\u003e closed issuance guarantees that no other token of the same type will\n\u003e ever be issued.\n\u003e - The power to continue the issuance of an open token can be sent to\n\u003e another address, using a transaction. Once the power to continue the\n\u003e issuance is sent to someone, the former issuer cannot issue any more\n\u003e tokens.\n\u003e - The power to continue the issuance has the same features of\n\u003e plausible deniability of the possess of a token.\n\u003e - Since a token type is uniquely identified by a transaction hash, or,\n\u003e in some cases, by a Bitcoin address, a user can prove to be the issuer\n\u003e by signing a message using the Bitcoin protocol.\n\u003e - Future proof. Tokens can move following P2PKH, P2SH, P2SH-P2WPKH\n\u003e outputs or any other type of script\n\u003e - Blockchain pollution of the protocol transactions is almost zero.\n\u003e There is no OP_RETURN involved, nor any other type of \"fake\" addresses\n\u003e that pollute the UTXO database.\n\u003e - The protocol is based on the Bitcoin blockchain, but, with small\n\u003e changes, can be considered blockchain agnostic.\n\u003e - Atomic transactions between tokens and Bitcoin are possible.\n\u003e - Atomic transactions between different types of tokens are possible.\n\u003e - Tokens of different types can be held by the same address and by the\n\u003e same output.\n\u003e - Tokens can be divided indefintely, thus having any number of decimals.\n\u003e - Tokens can be issued automatically on the receiving of bitcoins.\n\u003e This operation performs a token offering issuance (also known as Initial\n\u003e Coin Offering).\n\u003e\n\u003e Introduction\n\u003e ============\n\u003e\n\u003e Where are the tokens?\n\u003e ---------------------\n\u003e As with bitcoins, tokens are contained in unspent Bitcoin outputs. In\n\u003e some cases, defined below, the last five digits of the satoshi value\n\u003e sent to the output represent the number of tokens contained in the output.\n\u003e\n\u003e When an output is spent, the tokens contained in the output are fully\n\u003e spent in the same transaction. There are no tokens outside of the tokens\n\u003e contained in the UTXO database.\n\u003e\n\u003e Token issuance\n\u003e --------------\n\u003e The large majority of bitcoin transactions can be semantically seen as\n\u003e token issuances. There are two types of token issuances: closed and\n\u003e opened. A closed token issuance guarantees that no other token of the\n\u003e same type will ever be issued.\n\u003e\n\u003e Issuance chains\n\u003e ---------------\n\u003e An open issuance gives to one, or more, of its output the power to\n\u003e continue the issuance of tokens of the same type. We define such a power\n\u003e as Power of Continuation (POC). The transaction that will spend the\n\u003e output appointed with the POC will be a continuation of the same\n\u003e issuance chain.\n\u003e\n\u003e Every transaction of the chain will issue the same type of token. On top\n\u003e of that, every transaction that is part of the chain, can also be seen\n\u003e as as issuance of tokens of its, new, type. A chain will be closed by a\n\u003e transaction having more than one output and the first output with five\n\u003e zeros as the last five digits of the satoshis value. No other\n\u003e transactions can send tokens of the same type after the close of the\n\u003e issuance.\n\u003e\n\u003e Token names\n\u003e -----------\n\u003e A token type can have multiple names. The default name is the hash of\n\u003e the first transaction that issued the token.\n\u003e\n\u003e i.e: 68330b6ab26e44f9c3e515f04d15ffe6547f29e60b809a47e50d9abf59045c1e\n\u003e\n\u003e As alternative names, a token type can be named after the bitcoin\n\u003e address of one of the outputs of the transaction that first issued the\n\u003e token, provided the fact that the address has never been used before in\n\u003e the blockchain.\n\u003e\n\u003e Note: it is better to use one of the alternate names in cases when\n\u003e transaction malleability is a concern.\n\u003e\n\u003e Vanity token names\n\u003e ------------------\n\u003e A token can be identified using only the first characters of the Bitcoin\n\u003e address, as alternate name defined above, if the characters are\n\u003e different from every previous Bitcoin address seen in the blockchain. An\n\u003e example is provided below.\n\u003e\n\u003e Tokens can coexist\n\u003e -------------------\n\u003e Token of different types can coexist in a single output while remaining\n\u003e of different types. Thus a bitcoin address (actually an output of the\n\u003e UTXO database) can hold tokens of different types. Every Bitcoin address\n\u003e contains a lot of types of tokens, so that a user usually does not know\n\u003e all the type of tokens contained in an address.\n\u003e\n\u003e A single transaction can send a type of token to some of the outputs\n\u003e while sending another type of token to a different set of its outputs.\n\u003e Tokens are never burned or deleted.\n\u003e\n\u003e Use the protocol\n\u003e ================\n\u003e This section explains a basic use case. In all the examples provided, we\n\u003e do not consider the fee. We assume that there is another input, not\n\u003e listed, that pays the transaction fee.\n\u003e\n\u003e Alice, Bob, Charlie, and Daniel decides that they want to start a new\n\u003e company. Each of them will give to the new company some time, money,\n\u003e furniture, knowledge. They decide everyone contributed to the company\n\u003e with a percentage of value as follows: Alice - 40%, Bob - 12%, Charlie -\n\u003e 34% and Daniel - 14%. They decide that the shares of the new company can\n\u003e be freely resold to others and that they will accept that the annual\n\u003e meeting will consent vote through messages signed using the Bitcoin\n\u003e protocol by the owners of the shares.\n\u003e\n\u003e Issue tokens\n\u003e ------------\n\u003e Alice asks Bob, Charlie, and Daniel to send her 1 Bitcoin each. She asks\n\u003e each of them to give her a bitcoin address where they want to receive\n\u003e back the bitcoins along with the tokens.\n\u003e\n\u003e She asks Charlie to generate a vanity address that has never been used\n\u003e before of type 1CompanyXWXjLgud9jxwxm34u.... Since there has been a\n\u003e previous address in the blockchain having 1Companx as the first\n\u003e characters, but this is the first address seen in the blockchain that\n\u003e has 1Company as the first characters, they will call the token with the\n\u003e name 1Company. This step is optional.\n\u003e\n\u003e Then she sends, from her wallet, a transaction having the following\n\u003e outputs:\n\u003e\n\u003e - 1.00000040 to an address controlled by Alice\n\u003e - 1.00000012 to an address controlled by Bob\n\u003e - 1.00000034 to the vanity address 1CompanyXWXjLgud9jxwxm34u...\n\u003e controlled by Charlie\n\u003e - 1.00000014 to an address controlled by Daniel\n\u003e - 3.45322112 is the change generated by Alice's wallet\n\u003e\n\u003e This transaction gives 40, 12, 34, 14 tokens to each one. The newly\n\u003e generated token type can be named after the transaction hash, or after\n\u003e the vanity address (optional), or after one of the addresses of the\n\u003e persons involved, provided that the address has never been used before.\n\u003e\n\u003e The issuance is still open. Since they do not want to issue more shares,\n\u003e they decide to close the issuance (on the other side, they could decide\n\u003e to leave the issuance open and to hold the issuing key somewhere, or to\n\u003e have a multisignature address and to give the keys to the directors of\n\u003e the company). In order to close the issuance, Alice generates the\n\u003e following transaction that sends bitcoins from her wallet to addresses\n\u003e of her same wallet, using the change output of the previous transaction\n\u003e as an input:\n\u003e\n\u003e - 0.45000000 to an address of her wallet\n\u003e - 3.00322112 change generated by the wallet\n\u003e\n\u003e This closes the issuance.\n\u003e\n\u003e Send tokens\n\u003e --------------\n\u003e After some while, Bob decides to give some shares of the company to his\n\u003e husband Giacomo. He generates a new transaction spending the output of\n\u003e the issuance transaction:\n\u003e\n\u003e - 0.03400008 to Giacomo\n\u003e - 0.96600004 change generated by Bob's wallet\n\u003e\n\u003e This transaction gives to Giacomo 8 shares of the company.\n\u003e\n\u003e Atomic transactions\n\u003e -------------------\n\u003e Daniel wants to sell 3 of his 14 shares to Frank. They negotiate a price\n\u003e of 0.00323200 bitcoin per share. This is a total of 0.00969600 bitcoin\n\u003e to buy the three shares. They do not know each other very well, so they\n\u003e decide to make an atomic transaction that will give 0.00969600 bitcoins\n\u003e to Daniel and 3 shares to Frank. Daniel set an input of the new\n\u003e transaction with his issuance transaction output. Frank put in another\n\u003e input of 1.23242454 bitcoins from his wallet. The outputs of the\n\u003e transaction are as follows:\n\u003e\n\u003e - 0.22400003 to an address controlled by Frank (this gives the 3\n\u003e shares to Frank)\n\u003e - 0.23200000 to an address controlled by Daniel (this is part of the\n\u003e payment to Daniel)\n\u003e - 0.77769614 to an address controlled by Daniel (this can be\n\u003e considered the change of the original issuance output of 1.00000014)\n\u003e - 0.99872851 to an address controlled by Frank (change to Frank)\n\u003e\n\u003e Daniel sent to the inputs of the transaction 1.00000014 bitcoins and\n\u003e receives back 1.00969614. This gives to Daniel the 0.00969600 paid by\n\u003e Frank. On the other side, Frank sends 1.23242454 as an input of the\n\u003e transaction and receives back 1.22272854 bitcoins, thus paying exactly\n\u003e the 0.00969600 that needs to be paid to Daniel. This transaction sends 3\n\u003e tokens from Daniel to Frank. Another 11 tokens are the tokens that are\n\u003e given as a change to Daniel, along with 0.23200000 bitcoins.\n\u003e\n\u003e Specification\n\u003e =============\n\u003e\n\u003e Definitions\n\u003e -----------\n\u003e In order to evaluate a transaction, the outputs are sorted by the\n\u003e satoshis value. Once sorted, we define a \"cut\" output the first output\n\u003e having five zeros as the last five digits of the satoshi value (satoshis\n\u003e modulo 10^5 == 0). In the following, \"first\", \"second\", \"last\" are all\n\u003e referred to the sorted outputs.\n\u003e\n\u003e We define as \"signal\" of an output the value of satoshis of the output\n\u003e modulo 10^5. This is the last five digits of the value, as expressed in\n\u003e satoshis.\n\u003e\n\u003e Despite not mandatory, we sometimes call \"c\", or \"change\", the output\n\u003e having the biggest value in Satoshi. This is the last output, as sorted\n\u003e above. Such behavior follows the \"Guidelines\" section, explained below.\n\u003e\n\u003e We use n=0 related to a sequence a1, ..., an, to indicate that there are\n\u003e no elements in the sequence.\n\u003e\n\u003e Issuance of a token\n\u003e -------------------\n\u003e A transaction that has only one output, or has the first output that is\n\u003e a cut, issues no token. Every other Bitcoin transaction is an issuance\n\u003e of tokens of the type of the transaction.\n\u003e\n\u003e When a issuance is open, Power of Continuation (POC), will be given to\n\u003e an output that will be spent in a transaction that continues the\n\u003e issuance of the same type of tokens.\n\u003e\n\u003e As for the protocol behavior, we divide the structure of the sorted\n\u003e outputs of a bitcoin transaction in the following groups. For each\n\u003e group, a description of the behavior of the protocol is provided.\n\u003e\n\u003e - a1, ..., an, cut(POC), z1(POC), ... zm(POC), b1, ..., bl, with n\u003e0,\n\u003e m\u003e=0, m+l\u003e0\n\u003e * zi are outputs signaling zero. They are optional.\n\u003e * This is an open issuance. It generates the number of tokens\n\u003e signaled by the outputs before the cut: a1, ..., an. Every output of\n\u003e that set receives a number of tokens as signaled by the output satoshis'\n\u003e value.\n\u003e * The cut output, and every other output zi, signaling zero, that\n\u003e is directly after the cut, receive the POC. This means that the\n\u003e transactions that will spend the POC will be a continuation of this\n\u003e issuance and a continuation of every issuance that gave the POC to the\n\u003e this transaction.\n\u003e - cut, b1, ..., bm with m\u003e0 (a cut alone is a case of the fourth type)\n\u003e * This is a particular case of the first group, having n=0 and\n\u003e m=0. This transaction *closes the issuance forever*. Every token's chain\n\u003e that ends into this transaction is closed as well.\n\u003e * It generates no tokens and there are no other outputs that can\n\u003e continue the issuance in the future.\n\u003e * If b1 or b2 have a signal of zero and m\u003e2, this is a token\n\u003e offering issuance transaction. It will be described in a following section.\n\u003e - a1, ..., an, c(POC) with n\u003e0\n\u003e * This is an open issuance. It generates the number of tokens that\n\u003e are signaled in a1, ..., an. The last output c will not receive tokens.\n\u003e * The last output c will receive the POC. A following transaction\n\u003e that spends the output c is an issuance transaction of the same type of\n\u003e token.\n\u003e * The fact that c is a cut (or not) does not modify the behavior\n\u003e of the transactions of this group\n\u003e - c(POC) (single output, also seen as the previous one, with n=0)\n\u003e * This transaction generates no tokens at all.\n\u003e * The output c receives the POC. Thus a following transaction that\n\u003e spends the output c is an issuance transaction of the same type of token.\n\u003e\n\u003e Notes on token issuances\n\u003e ------------------------\n\u003e The number of tokens generated by an issuance transaction is always the\n\u003e sum of the signals of all the outputs, excluding the last one and the\n\u003e outputs that are listed after a cut. Thus the number of tokens sent to\n\u003e each output, that receives tokens, is always the number signaled by the\n\u003e output.\n\u003e\n\u003e Who has the power to generate other tokens of the same issuance (POC):\n\u003e\n\u003e - If there is no cut, the issuance is open and the transaction that\n\u003e will spend the last (biggest) output can continue to generate token of\n\u003e the same type.\n\u003e - If there is a cut, in a position different than the first, the\n\u003e issuance is open. The cut output will be the input of a following\n\u003e transaction that issues more tokens of the same issuance chain. The\n\u003e following transaction can close tha chain, or can be an open issuance,\n\u003e thus having another output that will continue the generation chain.\n\u003e\n\u003e In order to close forever the issuance of tokens, the transaction should\n\u003e have a cut as the first output and have more than one output.\n\u003e\n\u003e Transfer of tokens\n\u003e ------------------\n\u003e Every bitcoin transaction spends all the tokens' content of the inputs\n\u003e and sends them to the outputs. Some of the outputs receive the number of\n\u003e tokens exactly stated in the last five digits of the satoshis sent (the\n\u003e signal), in a way similar to an issuance transaction.\n\u003e\n\u003e A transaction can be seen as having one of the three following shapes\n\u003e (ai means an output that is not a cut, bi and c are outputs that can be\n\u003e cut):\n\u003e\n\u003e - a1, ..., an, cut, b1, ..., bm, c (transactions with a cut) (n=0 is\n\u003e described here)\n\u003e * No output (bi) after a cut receives tokens.\n\u003e * Tokens will be assigned to outputs a1, ..., an trying to follow\n\u003e the signal as follows:\n\u003e - If there are enough tokens, the tokens signaled by the first\n\u003e output are assigned to that output.\n\u003e - If there are still remaining tokens, the tokens are sent to\n\u003e the following output based on the signal.\n\u003e - This continues until there is a cut or the tokens signaled\n\u003e by an output are more than the remaining tokens. In these cases:\n\u003e * If there is a cut, it receives all the remaining tokens.\n\u003e * If there is an output receiving more tokens than the\n\u003e remaining tokens (we define it a \"remaining error\"), the output receives\n\u003e no token at all. No other output will receive tokens after this and all\n\u003e the remaining tokens will be sent to the last output c (thus, if there\n\u003e is a cut in the transaction, the algorithm \"jumps\" the cut).\n\u003e * If there is a \"remaining error\" and the transaction is a\n\u003e special transaction as defined in the next section, and the number of\n\u003e tokens in input is exactly the same of the two types (big and small)\n\u003e that are the result of a previous split or join special transaction, the\n\u003e \"remaining error\" output gets one of the smallest tokens involved. This\n\u003e will be better explained in the following section about \"special\n\u003e transactions\".\n\u003e * If the first output is a cut, and the transaction is not a\n\u003e special one as defined below in the document, the last output (c)\n\u003e receives all the tokens\n\u003e - a1, ..., an, c (ai is not a cut, for every i; c can be a cut)\n\u003e * The tokens are assigned to a1, ..., an as described in the\n\u003e previous group.\n\u003e * The last output c receives all the remaining tokens. This\n\u003e behavior is not modified by the fact that the last output is a cut.\n\u003e - c (single output transaction, also seen as the previous one, with n=0)\n\u003e * The output receives all the tokens received from the inputs\n\u003e\n\u003e Transactions receiving both the POC of an issuance and some tokens of\n\u003e the same issuance\n\u003e\n\u003e ---------------------------------------------------------------------------------------\n\u003e The protocol is designed such that a transaction of an issuance chain\n\u003e never issue new tokens to an output, that receives the POC of the same\n\u003e type of token. But two different inputs can give to a transaction both\n\u003e some tokens and the POC of the same type of token. In this case, there\n\u003e is a double role for the transaction that is both a continuation of the\n\u003e issuance and a transfer transaction sending tokens of the same type.\n\u003e\n\u003e In this case, the tokens will be allocated as defined in the following\n\u003e four different shapes of transaction:\n\u003e\n\u003e - a1, ..., an, cut, b1, ..., bm, c (transaction with a cut)\n\u003e * The generated tokens are sent to the outputs a1, ..., an as\n\u003e described in the definition of an issuance of tokens\n\u003e * All the tokens received in input of the same type of the\n\u003e issuance we are continuing will be sent to the cut output\n\u003e - a1, ..., an, c (transaction without a cut, or with c that is a cut:\n\u003e ai is not a cut, for every i)\n\u003e * The generated tokens are sent to the outputs a1, ..., an as\n\u003e described in the definition of an issuance of tokens transaction\n\u003e * All the tokens received in input, of the same type of the\n\u003e issuance we are continuing, will be sent to the last output c\n\u003e - cut, b1, ..., bm\n\u003e * The issuance will be closed and all the tokens will be given to\n\u003e the last output bm. The behavior described in the issuance transaction\n\u003e and in the transaction sending tokens do not influence each other, in\n\u003e this case.\n\u003e * If it is a special transaction, as defined below, there is no\n\u003e overlap between the definitions. The issuance chain is closed and the\n\u003e received tokens will be given as defined.\n\u003e - c only\n\u003e * The definitions of issuance transaction and transfer transaction\n\u003e can be used. The issuance will remain open and the address will receive\n\u003e all the tokens received from the inputs\n\u003e\n\u003e Since both the first and the second group of transactions are giving the\n\u003e POC to the same output that receives the tokens, the output will\n\u003e continue to carry both the tokens received and the POC. This delegates\n\u003e someone to issue new tokens and allocates some tokens from a previous\n\u003e issuance that are still not assigned.\n\u003e\n\u003e Split and join transactions\n\u003e ---------------------------\n\u003e A split or join transaction is one that has one of the following formats\n\u003e of outputs:\n\u003e\n\u003e - cut, a1, ..., an, z, b1, ..., bm (z is an output signaling zero,\n\u003e like a cut)\n\u003e - cut, a1, ..., an, c\n\u003e\n\u003e having the added condition that the sum of the signals of the outputs\n\u003e a1, ..., an is:\n\u003e\n\u003e - equal to the number of tokens received in input divided by 1000 (we\n\u003e call it a join transaction), or\n\u003e - equal to the number of tokens received in input multiplied by 1000\n\u003e (we call it a split transaction)\n\u003e\n\u003e Since the presence of these two extra conditions, the fact that a\n\u003e transaction is a join or split transaction, or it is not (hence it is a\n\u003e simple transfer transaction), depends on the number of tokens received\n\u003e in the input. A given transaction can be both split or join for some\n\u003e type of tokens, and normal for other types of tokens.\n\u003e\n\u003e Note: this is the same format that closes an issuance chain. If the\n\u003e transaction receives both POC and tokens of the same type, the\n\u003e transaction chain will be closed and the received tokens will be sent as\n\u003e described here.\n\u003e\n\u003e Note: this is also the format of a transfer transaction that assigns to\n\u003e the change c or bm, the token received in the input. But, if a\n\u003e transaction is a special one of the first two types, that behavior\n\u003e should not be considered and no tokens will be transferred to the change.\n\u003e\n\u003e The split transaction generates a new type of tokens with a value that\n\u003e is one thousandth of the value of the type of tokens received in the\n\u003e input. This new type can be mixed with tokens generated by other similar\n\u003e split transactions, based on the same original token. Split tokens have\n\u003e the same value and can be joined in the future with join transactions.\n\u003e\n\u003e The join transaction generates a new type of tokens with one thousand\n\u003e times the value of the type of tokens received in the input. This new\n\u003e type of token can coexist with tokens generated by other similar join\n\u003e transactions, based on the same original token. Joined tokens from the\n\u003e same original token, have the same value and can be split in the future\n\u003e with split transactions. Thus becoming again original tokens.\n\u003e\n\u003e In a special transaction of the second group, without \"the second cut\"\n\u003e z, the change is mandatory and does not receive tokens. This means that\n\u003e the number of tokens sent is summed up without the last output. If the\n\u003e number is not correct, then it is not a split or join transaction.\n\u003e\n\u003e Tokens split or joined are of a different type than their original\n\u003e source. This means that they can coexist in the same output and will\n\u003e never mix together. Thus a output having 3 big tokens and 456 tokens\n\u003e obtained by a split transaction, seems to have 3.456 tokens, but, in\n\u003e fact, has 3 tokens of a type and 456 tokens of another type (the second\n\u003e type is referred as the original type with a 0.001 unit of measure).\n\u003e\n\u003e Note: as described below, there is a procedure of separating tokens of\n\u003e different types contained in the same output. This procedure will not\n\u003e work if the two type of tokens are present in the same output in the\n\u003e same number. Thus if an output contains exactly 3.003 tokens (3 big and\n\u003e 3 small), the tokens cannot be separated anymore. This is why we\n\u003e introduced, in the transfer transaction definition, the rule that\n\u003e assigns in this case one single token of the smallest type to the\n\u003e \"remaining error\" output.\n\u003e\n\u003e Token offering issuance transactions\n\u003e ------------------------------------\n\u003e A token offering issuance transaction is a transaction having one of the\n\u003e following formats (z is an output signaling zero, like a cut; r and s\n\u003e are outputs that signal a value greater than zero; the group of outputs\n\u003e (t1, t2, z) is optional; t1 or t2 can signal zero, but not both):\n\u003e\n\u003e - cut, z, r, (t1, t2, z,) a1, ..., an, c\n\u003e * price of tokens are predefined\n\u003e - cut, s, z, (t1, t2, z,) a1, ..., an, c\n\u003e * price of tokens are not predefined\n\u003e\n\u003e The tokens will be assigned to one of the outputs of every transaction\n\u003e that sends bitcoin to the address of the outputs r or s, as follows:\n\u003e - if the sending transaction has only two outputs (r, c), (c, r), (s,\n\u003e c) or (c, s), the \"other\" output c receives the tokens.\n\u003e - if the sending transaction has more than two outputs, the last\n\u003e (biggest) output that is not the one sending bitcoins to r or s, will\n\u003e receive the tokens.\n\u003e - if the sending transaction has only one output, the generated tokens\n\u003e will be assigned to the output r or s itself. This can be considered as\n\u003e a donation: it generates tokens, but the tokens remain in the\n\u003e availability of the issuer.\n\u003e - since the number of token emitted is always an integer, the\n\u003e remaining satoshis are not considered in the number of tokens issued and\n\u003e are sent to the issuer without any token generation.\n\u003e\n\u003e Note: this is the second place, in this document, where the bitcoin\n\u003e address of an output is used. The other place regards the alternate\n\u003e names of an issuance. Everything else in the protocol is based on\n\u003e outputs, not addresses.\n\u003e\n\u003e If the group (t1, t2, z) is present, it signals how many token will be\n\u003e issued. The total number of tokens that will be issued is the number\n\u003e signaled by t1 * 10^6 + the number signaled by t2. In any block, the\n\u003e issuance can be closed by the transaction that spends the outputs r or s.\n\u003e\n\u003e Timeline:\n\u003e - The offer starts in the block that contains the token offering\n\u003e issuance transaction. Every transaction of the starting block receives\n\u003e tokens, without order.\n\u003e - If there is a defined total number of tokens, the issuance will end\n\u003e when the total number of tokens has been reached.\n\u003e * Inside the last block, the transactions are considered in the\n\u003e order they are listed. So if a transaction takes the last tokens, every\n\u003e other transaction sending bitcoins to r or s, do not receive tokens.\n\u003e - The transaction that spends the outputs r or s ends the issuance.\n\u003e This transaction suspends the issuance even if a defined number of\n\u003e tokens was defined in the token offering issuance transaction.\n\u003e * In case of an issuance suspeded, or ended, by a transaction\n\u003e spending r or s, every transaction of the block containing the spending\n\u003e transaction will be considered valid as a receiver of tokens.\n\u003e * Thus, sending bitcoins to the address of the outputs r or s will\n\u003e be considered as part of the offering, only if it is included in a block\n\u003e between the block of the transaction that has r or s as an output\n\u003e (start), and the block of the transaction that spends the output r or s\n\u003e (end), inclusive.\n\u003e\n\u003e A token offering issuance transaction of the first type permits to set a\n\u003e rate, and to issue tokens every time bitcoins are received by an\n\u003e address. The rate is defined by the number signaled by the output r. One\n\u003e token will be issued for every r satoshis received.\n\u003e\n\u003e A token offering issuance transaction of the second type does not set a\n\u003e predefined rate at the start. The rate will be defined by the\n\u003e transaction that closes the issuance by spending the output s. The first\n\u003e (smallest) output of the closing transaction, or the first output after\n\u003e the cut (if a cut is present), will signal the rate. This type of token\n\u003e offering issuance, having the price defined at the end, permits to issue\n\u003e token based on parameters related to the issuance itself. This is the\n\u003e case, for example, of Dutch Auctions.\n\u003e\n\u003e Note: A token offering issuance transaction can be seen as a transfer\n\u003e transaction, that sends all the tokens that receives to the output c.\n\u003e\n\u003e Note: the type of token issued is defined by the token offering issuance\n\u003e transaction, seen as an issuance transaction. Since a token offering\n\u003e transaction is also the closure of some issuing chains, this means that\n\u003e the same token offer will issue different type of tokens. In fact, a\n\u003e different type of token will be issued for every issuance chain that\n\u003e ends with the same token offering issuance transaction. Thus a token\n\u003e type can be first issued in a controlled way (this is usually called\n\u003e pre-ICO) and then the rate can be stated, and the same type of token can\n\u003e be offered to the public (this is usually called the ICO). Since the\n\u003e token offering issuance transaction closes the issuance forever, there\n\u003e is the guarantee that no other tokens of the same type will ever be\n\u003e issued after the offer is closed. In order to offer tokens at different\n\u003e prices, multiple issuance transactions can be generated with POCs\n\u003e originating from the same issuance chain.\n\u003e\n\u003e Atomic transactions between bitcoins and tokens\n\u003e -----------------------------------------------\n\u003e Using the cut signal and software that allows full \"coin selection\",\n\u003e it's possible to make atomic exchange transactions. The outputs before\n\u003e the cut will determine who will receive the tokens and the following\n\u003e outputs will define the rest of the transaction. Both the changes (the\n\u003e one of the token wallet and the one of the Bitcoin wallet), should be in\n\u003e the second set (after the cut). Since the cut will receive the remaining\n\u003e tokens, it is suggested that the cut is sent to the seller of tokens.\n\u003e Using this method, the remaining tokens can be sent without involving a\n\u003e calculation of the remaining tokens. The outputs of an atomic exchange\n\u003e transaction will have the following format (seller is the token seller,\n\u003e buyer is the token buyer).\n\u003e\n\u003e - a1: tokens sent from the seller to the buyer\n\u003e - a2: tokens sent from the seller to the buyer\n\u003e - cut: part of the bitcoin payment sent from buyer to seller\n\u003e - b1: part of the bitcoin payment sent from buyer to seller (or change\n\u003e sent from seller to buyer, if the price to be paid is less than the\n\u003e value of the cut)\n\u003e - b2: Bitcoin change sent to the token wallet\n\u003e - b3: Bitcoin change sent to the bitcoin wallet\n\u003e\n\u003e It is impossible to make an atomic exchange transaction if the wallet in\n\u003e use does not allow coin selection.\n\u003e\n\u003e Cross token atomic transactions\n\u003e -------------------------------\n\u003e Let's say that Alice wants to sell a number x of tokens of type Ta and\n\u003e Bob wants to pay using y tokens of type Tb. Token of type Tb are of\n\u003e lesser value than the tokens of type Ta, so Bob will pay more Tb tokens\n\u003e and Alice will pay fewer Ta tokens (x \u003c y). Let's say that the\n\u003e transaction spends an output from Alice containing BTCa bitcoins and\n\u003e *exactly* x tokens, while Bob sends to the same transaction BTCb\n\u003e bitcoins and a number z of tokens of type Tb. Since z \u003e y, Bob will\n\u003e receive a change c in tokens of type Tb.\n\u003e\n\u003e Alice managed the previous transactions so that a fixed number x of\n\u003e tokens can be sent as the input with a number BTCa of bitcoins. Bob is\n\u003e not required do the same, because there is the cut that gives the\n\u003e remaining tokens back to Bob. In order to simplify let's say that there\n\u003e is another input giving the fee for the transaction and the Bitcoin\n\u003e assigned to each output will be calculated accordingly.\n\u003e\n\u003e The atomic transaction can be made by signaling with the first output\n\u003e the number y of tokens that Bob should pay to Alice. This output will go\n\u003e to Alice. Since y is higher than x, all the x tokens of type Ta will go\n\u003e to the change (directed to Bob), while the y tokens of type Tb will go\n\u003e to the first output. A following cut can be used to send the change to\n\u003e Bob. The addresses following the cut can be used as changes of bitcoins.\n\u003e\n\u003e The inputs of the transaction will have a content in Bitcoin and tokens\n\u003e as follows:\n\u003e\n\u003e - Alice will spend an output having BTCa bitcoins and containing\n\u003e *exactly* x tokens of type Ta\n\u003e - Bob will spend an output having BTCb bitcoins and containing y + c\n\u003e tokens of type Tb\n\u003e\n\u003e The outputs of the transaction will have the following form:\n\u003e\n\u003e - Bitcoin sent: BTCa1; Signal sent: y; Directed to Alice (the output\n\u003e gets y tokens of type Tb, but does not get any token of type Ta, because\n\u003e x \u003c y)\n\u003e - Bitcoin sent: BTCb1; Signal sent: cut; Directed to Bob (no token of\n\u003e type Ta given, but receives c tokens of type Tb)\n\u003e - Bitcoin sent: BTCa - BTCa1; Signal sent: not important; Directed to\n\u003e Alice (no token sent, but useful to send a change in Bitcoin to Alice,\n\u003e if needed)\n\u003e - Bitcoin sent: BTCb - BTCb1; Signal sent: not important; Directed to\n\u003e Bob (this output gets number x tokens of type Ta)\n\u003e\n\u003e Cross token atomic transactions in the case of the same number of tokens\n\u003e to be exchanged\n\u003e\n\u003e ----------------------------------------------------------------------------------------\n\u003e The atomic transactions described above do not work if the value of\n\u003e tokens of type Ta is equal to the value of tokens of type Tb. In this\n\u003e case, there is no way of doing an atomic exchange.\n\u003e\n\u003e Let's say that we need to do a transaction between two tokens that have\n\u003e the same value: TetherA and TetherB. Let's say that Alice and Bob want\n\u003e to change 199 tokens. The atomic transaction cannot be made, but, with a\n\u003e small risk, two transactions can be made. The first will be an atomic\n\u003e transaction giving 100 tokens of type TetherA from Alice to Bob and\n\u003e receiving 99 of type TetherB back, and the second will be 99 to 100.\n\u003e\n\u003e How to separate different types of token\n\u003e ----------------------------------------\n\u003e Let's say that an output contains two different types of tokens of\n\u003e interest to the user. Is there a way to separate the tokens so that they\n\u003e can be sent to different outputs? If the tokens are exactly the same\n\u003e number, there is not. If the tokens are two different numbers: x tokens\n\u003e of type A and y tokens of type B, then the separation can be done. Since\n\u003e the \"remaining error\" of an output goes to the change, we can send the\n\u003e higher value of the two and have the change receive the lower. We assume\n\u003e that x \u003c y.\n\u003e\n\u003e Let's call A1 the output that will receive A and B1 the output that will\n\u003e receive the tokens of type B.\n\u003e\n\u003e The transaction will be similar to the cross token atomic transaction:\n\u003e\n\u003e - Signal sent: x (the output gets x tokens of type B, but does not get\n\u003e any token of type A, because x \u003c y)\n\u003e - Signal sent: cut (no token of type A given, but receives a change in\n\u003e token of type B if the previous signal was less than y)\n\u003e - Other outputs\n\u003e - Signal sent: not important (this output gets number x tokens of type A)\n\u003e\n\u003e Guidelines\n\u003e ==========\n\u003e There are some suggestions that, if followed by the user, permit\n\u003e managing tokens in a simple manner, without technical knowledge of the\n\u003e rest of the protocol, with plausible deniability. This can be done using\n\u003e any existing wallet.\n\u003e\n\u003e The guidelines described here are based on a wallet that will be\n\u003e \"consolidated\". This means that all the outputs of the wallet are linked\n\u003e toghether. In some cases, this behavior diminish the level of privacy of\n\u003e the user. Thus, it is advised to use a number of different wallets, in\n\u003e order to reach the desired level of privacy.\n\u003e\n\u003e Plausible deniability: how to use a wallet to manage tokens\n\u003e -----------------------------------------------------------\n\u003e Some of the protocol's operations are designed to be managed using a\n\u003e coin selection software, however, any wallet without coin selection can\n\u003e be used to generate, send, or receive tokens. The option to use any\n\u003e existing Bitcoin wallet is the base of the plausible deniability of the\n\u003e protocol. The user can send, receive and generate tokens by using any\n\u003e wallet in a way that seems a normal use of the Bitcoin protocol to\n\u003e manage bitcoins.\n\u003e\n\u003e Thus, the guidelines in this section are based on a use of a wallet by a\n\u003e user without involving any \"coin selection\".\n\u003e\n\u003e In order to send or generate tokens, the user needs to have, at any\n\u003e time, only one output in the wallet. Let's call it a \"consolidated\"\n\u003e wallet. In order to consolidate a wallet:\n\u003e\n\u003e - Send all the bitcoins contained in the wallet to a new address of\n\u003e the same wallet\n\u003e\n\u003e If the user departs from these guidelines by mistake, he can \"fix\" his\n\u003e wallet and re-consolidate it without losing the tokens contained in the\n\u003e wallet. If the wallet is consolidated, it remains consolidated while\n\u003e tokens are generated or sent, and while bitcoins from the wallet are\n\u003e spent. If bitcoins or tokens are received by any address of the wallet,\n\u003e then the wallet needs to be consolidated again.\n\u003e\n\u003e Issuance of tokens\n\u003e ------------------\n\u003e In order to generate tokens:\n\u003e\n\u003e - Consolidate the wallet if it is not already consolidated.\n\u003e - Send a minority of the bitcoins contained in the wallet to a new\n\u003e address (outside of the wallet). The last five digits of the satoshis\n\u003e sent are the number of tokens generated.\n\u003e - From the same wallet, other tokens can be generated by sending again\n\u003e a number of satoshis, having the last five digits that are the number of\n\u003e tokens to issue to the new address.\n\u003e - The value of bitcoins sent should always be less than the bitcoin\n\u003e that remains in the wallet\n\u003e - If during the process of generating tokens the wallet receives\n\u003e bitcoins, it should be consolidated again before continuing to generate\n\u003e tokens.\n\u003e - The type (or name) of tokens will be the txid of the transaction. If\n\u003e the transaction sends bitcoin to a new, never used, address, the address\n\u003e can be used as the name of the tokens, as well.\n\u003e\n\u003e In order to give the power to generate new tokens to another person:\n\u003e\n\u003e - Send all the Bitcoin content of the wallet to the other person, with\n\u003e a single transaction\n\u003e\n\u003e In order to close an issuance:\n\u003e\n\u003e - To close the issuance and guarantee that no other tokens of this\n\u003e type will ever be generated again, send to another address of the same\n\u003e wallet a number of bitcoins with the last five digits of the satoshis\n\u003e that is zero. Be aware that this shouldn't be all the content of the\n\u003e wallet. If all the content of the wallet is sent to some address, the\n\u003e issuance will not be closed. Instead, this gives to the receiver the\n\u003e power to generate new tokens.\n\u003e\n\u003e Spending bitcoins and not tokens\n\u003e --------------------------------\n\u003e In order to spend bitcoins from the wallet without sending any tokens,\n\u003e the user should spend less than half of the bitcoin value contained in\n\u003e the wallet, and:\n\u003e\n\u003e - Spend a number of satoshis where the last five digits are all zeros,\n\u003e or\n\u003e - Spend a number of satoshis where the last five digits are a number\n\u003e greater than the tokens that are in the wallet,\n\u003e\n\u003e Transfer of tokens\n\u003e ------------------\n\u003e In order to send tokens to another person:\n\u003e\n\u003e - Consolidate the wallet if it is not already consolidated.\n\u003e - Send a value less than half of the content of the wallet and having\n\u003e the number of satoshis where the last five digits are the number of\n\u003e tokens that need to be transferred,\n\u003e or\n\u003e - Send all the bitcoins of the wallet (even if the wallet is not\n\u003e consolidated).\n\u003e\n\u003e If the user sends all the content of the wallet to a single address (no\n\u003e change), then he's emptying the token content from the wallet, as well.\n\u003e All the tokens will go to the address and nothing will remain to the user.\n\u003e\n\u003e In order to receive tokens from other users:\n\u003e\n\u003e - Give to the other person a Bitcoin address of the wallet and ask to\n\u003e send tokens as explained above.\n\u003e - If the wallet was empty before of receiving tokens, then it is\n\u003e already consolidated. Instead, if the wallet already had some bitcoins,\n\u003e then the wallet needs to be consolidated before sending or generating\n\u003e tokens.\n\u003e\n\u003e Effects of the use of these guidelines\n\u003e --------------------------------------\n\u003e When using the guidelines, the number of tokens sent to the recipient is\n\u003e always stated in the last five digits of the satoshis sent. There are\n\u003e three exceptions:\n\u003e\n\u003e - In a single output transaction, all the tokens of the wallet will be\n\u003e sent to the recipient.\n\u003e - In a transaction where the amount of satoshis sent ends with five\n\u003e zeros, no tokens are sent.\n\u003e - In a transaction sending more tokens than the number of tokens of\n\u003e that type held in the wallet, no tokens are sent.\n\u003e\n\u003e Technical notes\n\u003e ---------------\n\u003e - Sending a number of bitcoins that is greater than half of the\n\u003e bitcoins contained in the wallet brings to unpredicted results.\n\u003e - Thus, if there are not enough bitcoins to continue to operate, the\n\u003e wallet needs to be \"re-charged\" by sending some bitcoins to it. By doing\n\u003e so, there will be more than one UTXO in the wallet. This departs from\n\u003e \"consolidated mode\" and the wallet needs to be consolidated again.\n\u003e - A consolidated wallet contains only one UTXO.\n\u003e - Every transaction made from a consolidated wallet contains only two\n\u003e outputs: one is the address outside of the wallet, and the other is the\n\u003e change.\n\u003e - Every transaction spends all the content of the wallet.\n\u003e\n\u003e Reference Implementation\n\u003e ========================\n\u003e A reference implementation will be included when the protocol will be\n\u003e reviewed and accepted by the community.\n\u003e _______________________________________________\n\u003e bitcoin-dev mailing list\n\u003e bitcoin-dev at lists.linuxfoundation.org\n\u003e https://lists.linuxfoundation.org/mailman/listinfo/bitcoin-dev\n\u003e\n-- \nAlex Kravets\n@alexkravets \u003chttps://twitter.com/alexkravets\u003e\n-------------- next part --------------\nAn HTML attachment was scrubbed...\nURL: \u003chttp://lists.linuxfoundation.org/pipermail/bitcoin-dev/attachments/20170908/883d0e5e/attachment-0001.html\u003e",
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