📅 Original date posted:2018-12-03
📝 Original message:I have a suggestion. If you are concerned about plausible deniability,
then it might make sense to just have the single mnemonic seed lead to a
single xprv key (as usual) and then do a private key derivation from that
based on a password string. The password can be simple, as it is based on
the security of the seed, just as long as the user feels they need for
deniability.
A simple reverse scheme like you describe would just be another thing a
person would know to check if given some seed so I don't see it as
providing much value, but I could be missing something.
On Mon, Dec 3, 2018 at 10:45 AM Steven Hatzakis via bitcoin-dev <
bitcoin-dev at lists.linuxfoundation.org> wrote:
> Hi All,
>
> I've developed a method to check if a mnemonic is also valid when the
> words are put into reverse order (not the entropy), where a given 12 or
> 24-word mnemonic could be valid both in little endian and big endian
> format. I've coined these "Palindromic Mnemonics", but perhaps more
> user-friendly is "reversible mnemonics."
>
> Purpose:
> A checksum-valid reversible mnemonic allows two separate vaults to be
> connected to the same mnemonic string of words, where all a users must do
> is enter the words in reverse order (the last word becomes first, second to
> last becomes second, and so on) to access the secondary (reversed words)
> vault. This utility could provide multiple use-cases, including related to
> combinations with passphrases and plausible deniability, as well as
> conveniences for those wishing to use a separate vault tied to the same
> string of words.
>
> Security:
> For any randomly generated 12-word mnemonic (128-bits of security) the
> chances of it also being reversible are 1/16 (I believe), as a total of 4
> bit positions must be identical (4 bits from the normal mnemonic and
> another 4 bits from the reversed string must match). For a 24-word
> mnemonic, those values increase to 8 bits which need to match 8 bits from
> the reversed string, leading to about 1 in every 256 mnemonics also being
> reversible. While the message space of valid reversible mnemonics should be
> 2^124 for 12 words, that search must still be conducted over a field of 2^128,
> as the hash-derived checksum values otherwise prevent a way to
> deterministically find valid reversible mnemonics without first going
> through invalid reversible ones to check. I think others should chime in on
> whether they believe there is any security loss, in terms of entropy bits
> (assuming the initial 128 bits were generated securely). I estimate at most
> it would be 4-bits of loss for a 12-word mnemonic, but only if an attacker
> had a way to search only the space of valid reversible mnemonics (2**124)
> which I don't think is feasible (could be wrong?). There could also be
> errors in my above assumptions, this is a work in progress and sharing it
> here to solicit initial feedback/interest.
>
> I've already written the code that can be used for testing (on GitHub user
> @hatgit), and when run from terminal/command prompt it is pretty fast to
> find a valid reversible mnemonics, whereas on IDLE in Python on a 32-bit
> and 64-bit machine it could take a few seconds for 12 words and sometimes
> 10 minutes to find a valid 24-word reversible mnemonic.
> Example 12 words reversible (with valid checksum each way):
>
> limit exact seven clarify utility road image fresh leg cabbage hint canoe
>
> And Reversed:
>
> canoe hint cabbage leg fresh image road utility clarify seven exact limit
>
>
> Example 24 reversible:
>
> favorite uncover sugar wealth army shift goose fury market toe message
> remain direct arrow duck afraid enroll salt knife school duck sunny grunt
> argue
>
> And reversed:
>
> argue grunt sunny duck school knife salt enroll afraid duck arrow direct
> remain message toe market fury goose shift army wealth sugar uncover
> favorite
>
>
> My two questions 1) are how useful could this be for
> you/users/devs/service providers etc.. and 2) is any security loss
> occurring and whether it is negligible or not?
>
> Best regards,
>
> Steven Hatzakis
> _______________________________________________
> bitcoin-dev mailing list
> bitcoin-dev at lists.linuxfoundation.org
> https://lists.linuxfoundation.org/mailman/listinfo/bitcoin-dev
>
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Joseph Gleason ⑈ [ARCHIVE] /
npub1qp…my8sw
2023-06-07 18:15:29
in reply to nevent1q…ss2l
Author Public Key
npub1qp59a7k7vxv0k8z277f50092ljk9mjg5du9lz8hlft37u4ggwqes5my8swPublished at
2023-06-07 18:15:29Event JSON
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"content": "📅 Original date posted:2018-12-03\n📝 Original message:I have a suggestion. If you are concerned about plausible deniability,\nthen it might make sense to just have the single mnemonic seed lead to a\nsingle xprv key (as usual) and then do a private key derivation from that\nbased on a password string. The password can be simple, as it is based on\nthe security of the seed, just as long as the user feels they need for\ndeniability.\n\nA simple reverse scheme like you describe would just be another thing a\nperson would know to check if given some seed so I don't see it as\nproviding much value, but I could be missing something.\n\nOn Mon, Dec 3, 2018 at 10:45 AM Steven Hatzakis via bitcoin-dev \u003c\nbitcoin-dev at lists.linuxfoundation.org\u003e wrote:\n\n\u003e Hi All,\n\u003e\n\u003e I've developed a method to check if a mnemonic is also valid when the\n\u003e words are put into reverse order (not the entropy), where a given 12 or\n\u003e 24-word mnemonic could be valid both in little endian and big endian\n\u003e format. I've coined these \"Palindromic Mnemonics\", but perhaps more\n\u003e user-friendly is \"reversible mnemonics.\"\n\u003e\n\u003e Purpose:\n\u003e A checksum-valid reversible mnemonic allows two separate vaults to be\n\u003e connected to the same mnemonic string of words, where all a users must do\n\u003e is enter the words in reverse order (the last word becomes first, second to\n\u003e last becomes second, and so on) to access the secondary (reversed words)\n\u003e vault. This utility could provide multiple use-cases, including related to\n\u003e combinations with passphrases and plausible deniability, as well as\n\u003e conveniences for those wishing to use a separate vault tied to the same\n\u003e string of words.\n\u003e\n\u003e Security:\n\u003e For any randomly generated 12-word mnemonic (128-bits of security) the\n\u003e chances of it also being reversible are 1/16 (I believe), as a total of 4\n\u003e bit positions must be identical (4 bits from the normal mnemonic and\n\u003e another 4 bits from the reversed string must match). For a 24-word\n\u003e mnemonic, those values increase to 8 bits which need to match 8 bits from\n\u003e the reversed string, leading to about 1 in every 256 mnemonics also being\n\u003e reversible. While the message space of valid reversible mnemonics should be\n\u003e 2^124 for 12 words, that search must still be conducted over a field of 2^128,\n\u003e as the hash-derived checksum values otherwise prevent a way to\n\u003e deterministically find valid reversible mnemonics without first going\n\u003e through invalid reversible ones to check. I think others should chime in on\n\u003e whether they believe there is any security loss, in terms of entropy bits\n\u003e (assuming the initial 128 bits were generated securely). I estimate at most\n\u003e it would be 4-bits of loss for a 12-word mnemonic, but only if an attacker\n\u003e had a way to search only the space of valid reversible mnemonics (2**124)\n\u003e which I don't think is feasible (could be wrong?). There could also be\n\u003e errors in my above assumptions, this is a work in progress and sharing it\n\u003e here to solicit initial feedback/interest.\n\u003e\n\u003e I've already written the code that can be used for testing (on GitHub user\n\u003e @hatgit), and when run from terminal/command prompt it is pretty fast to\n\u003e find a valid reversible mnemonics, whereas on IDLE in Python on a 32-bit\n\u003e and 64-bit machine it could take a few seconds for 12 words and sometimes\n\u003e 10 minutes to find a valid 24-word reversible mnemonic.\n\u003e Example 12 words reversible (with valid checksum each way):\n\u003e\n\u003e limit exact seven clarify utility road image fresh leg cabbage hint canoe\n\u003e\n\u003e And Reversed:\n\u003e\n\u003e canoe hint cabbage leg fresh image road utility clarify seven exact limit\n\u003e\n\u003e\n\u003e Example 24 reversible:\n\u003e\n\u003e favorite uncover sugar wealth army shift goose fury market toe message\n\u003e remain direct arrow duck afraid enroll salt knife school duck sunny grunt\n\u003e argue\n\u003e\n\u003e And reversed:\n\u003e\n\u003e argue grunt sunny duck school knife salt enroll afraid duck arrow direct\n\u003e remain message toe market fury goose shift army wealth sugar uncover\n\u003e favorite\n\u003e\n\u003e\n\u003e My two questions 1) are how useful could this be for\n\u003e you/users/devs/service providers etc.. and 2) is any security loss\n\u003e occurring and whether it is negligible or not?\n\u003e\n\u003e Best regards,\n\u003e\n\u003e Steven Hatzakis\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-------------- next part --------------\nAn HTML attachment was scrubbed...\nURL: \u003chttp://lists.linuxfoundation.org/pipermail/bitcoin-dev/attachments/20181203/4182bf2d/attachment.html\u003e",
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