Andreas Schildbach [ARCHIVE] on Nostr: 📅 Original date posted:2014-03-20 📝 Original message:On 03/20/2014 03:22 AM, ...
📅 Original date posted:2014-03-20
📝 Original message:On 03/20/2014 03:22 AM, Alex Kotenko wrote:
> Right now, before BIP70, I'm sending BIP21 URI via NFC or QR code, and I
> need to still be able to use it for backwards compatibility. But at the
> same time I want to be able to support BIP70. And also I want to avoid
> using external servers, the concept of my POS is that everything is
> happening between just payer's phone and payee's POS device. This means
> that BIP72 HTTP(S) link inside Bitcoin URI is not suitable for me.
We could use Bluetooth in the "r" parameter, not unlike we use Bluetooth
in the payment_url. However, since multiple devices could access your
machine at the same time, we need some for of adressibility of different
payment requests. Something like
"bt:<btmac>-<random_id_of_payment_request>".
> You're also offering an option to include Base43 encoded PR body right
> inside the Bitcoin URI, but in a way that is not backwards compatible
> with BIP21.
Well, do we need to be compatible? If the dev community decides Base43
PR QR's (or whatever other self-contained format) is the way to go, we
just implement, roll it out and use it.
> I understand your intention behind base43 encoding and noncompatible URI
> - you want to make most possible use of QR codes. But I wonder - did you
> compare this base43 to base64 encoded request in a binary QR code
> format? How much do we actually win in total bytes capacity at a price
> of noncompatibility and increased complexity?
Alphanumeric QR codes have an alphabet of 45 chars, of which I am using
43. I skipped Space and '%' because they're not allowed in URIs. When I
invented the Base43 format back in 2011, wanted it to be URI compatible
so we can use the Android intent dispatcher.
If we let go of the URI requirement, we can use binary QR codes as well.
This means users will always have to manually start their Bitcoin app
first. (Also, there is an implementation issue with the ZXing scanner
I'm using, it returns Strings rather than a byte array so it will choke
on \0 characters.)
> And also maybe we can extend BIP72 to include encoded payment request in
> the URL directly in a backwards compatible way?
I took this into consideration. It would be space inefficient.
The Base58-encoded address from BIP21 forces the QR code into binary
mode. Still you can't encode the payment request extension (probably an
URL parameter) as binary because it needs to stay compatible to the URI
standard (RFC 3986). You could use one of the Base64 variants for the PR
in this case, but still it would be inefficient.
Published at
2023-06-07 15:14:27Event JSON
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"created_at": 1686150867,
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"content": "📅 Original date posted:2014-03-20\n📝 Original message:On 03/20/2014 03:22 AM, Alex Kotenko wrote:\n\u003e Right now, before BIP70, I'm sending BIP21 URI via NFC or QR code, and I\n\u003e need to still be able to use it for backwards compatibility. But at the\n\u003e same time I want to be able to support BIP70. And also I want to avoid\n\u003e using external servers, the concept of my POS is that everything is\n\u003e happening between just payer's phone and payee's POS device. This means\n\u003e that BIP72 HTTP(S) link inside Bitcoin URI is not suitable for me.\n\nWe could use Bluetooth in the \"r\" parameter, not unlike we use Bluetooth\nin the payment_url. However, since multiple devices could access your\nmachine at the same time, we need some for of adressibility of different\npayment requests. Something like\n\"bt:\u003cbtmac\u003e-\u003crandom_id_of_payment_request\u003e\".\n\n\u003e You're also offering an option to include Base43 encoded PR body right\n\u003e inside the Bitcoin URI, but in a way that is not backwards compatible\n\u003e with BIP21.\n\nWell, do we need to be compatible? If the dev community decides Base43\nPR QR's (or whatever other self-contained format) is the way to go, we\njust implement, roll it out and use it.\n\n\u003e I understand your intention behind base43 encoding and noncompatible URI\n\u003e - you want to make most possible use of QR codes. But I wonder - did you\n\u003e compare this base43 to base64 encoded request in a binary QR code\n\u003e format? How much do we actually win in total bytes capacity at a price\n\u003e of noncompatibility and increased complexity?\n\nAlphanumeric QR codes have an alphabet of 45 chars, of which I am using\n43. I skipped Space and '%' because they're not allowed in URIs. When I\ninvented the Base43 format back in 2011, wanted it to be URI compatible\nso we can use the Android intent dispatcher.\n\nIf we let go of the URI requirement, we can use binary QR codes as well.\nThis means users will always have to manually start their Bitcoin app\nfirst. (Also, there is an implementation issue with the ZXing scanner\nI'm using, it returns Strings rather than a byte array so it will choke\non \\0 characters.)\n\n\u003e And also maybe we can extend BIP72 to include encoded payment request in\n\u003e the URL directly in a backwards compatible way?\n\nI took this into consideration. It would be space inefficient.\n\nThe Base58-encoded address from BIP21 forces the QR code into binary\nmode. Still you can't encode the payment request extension (probably an\nURL parameter) as binary because it needs to stay compatible to the URI\nstandard (RFC 3986). You could use one of the Base64 variants for the PR\nin this case, but still it would be inefficient.",
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