Support UR2.0 QR codes (for PSBTs)

[Jakob-1870]

UR 2.0 is becoming the standard for QR PSBT's. It's implemented in almost all software and hardware wallets that support QR PSBT's.
https://github.com/BlockchainCommons/Research

Electrum should add support for it.

[SomberNight]

https://github.com/BlockchainCommons/Research

There's a lot of stuff there... Which "spec" in particular are you referring to? Is it this one?
https://github.com/BlockchainCommons/Research/blob/master/papers/bcr-2020-005-ur.md

UR 2.0 is becoming the standard for QR PSBT's. It's implemented in almost all software and hardware wallets that support QR PSBT's.

Which other software/hardware/services support it?

[Jakob-1870]

Yes that's it.

Bluewallet, Sparrow, Specter, Keystone, Passport, Gordian, Krux, Seedsigner all use UR2.0.

[stepansnigirev]

Two python implementation that might be interesting for you:
From Foundation Devices: https://github.com/Foundation-Devices/foundation-ur-py
Implementation in Specter-DIY: https://github.com/diybitcoinhardware/f469-disco/tree/master/libs/common/microur

[massmux]

Sorry for duplicating the request i did not get aware of this one. But yes this would be important i think for all the community

[SomberNight]

Some previous discussion re the custom format we have been using since 2015: #5746
In short, when implementing PSBT support in 2019 we decided to keep using the base43 encoding inside alphanumeric-mode QR codes, instead of using either base64 text inside binary-mode QR codes or raw bytes inside binary-mode QR codes, due to maximising payload size and easy-copy-pasteability.

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Anyway, if this BCR-2020-005 format has traction, we could have it too. PR welcome. It probably needs some GUI-specific work, but getting it to work with the Qt GUI would be a good starting point.

The best way to transition would be to start always encoding using the new format, but support decoding using both.

[ecdsa]

I think it would be a pity if we were forced to adopt an animated qr code standard just because some spec is feature bloated.
Has someone taken the time to evaluate that?

[massmux]

actually sparrow and specter desktop use such a format. maybe it would be important electrum's users also can share same standard. imho

[Medgeina]

I too think that the use of QRcodes would be very practical. There would be less room for error, it takes away the fragility caused by the use of USB or SDcards... also, if everyone used the same standard, it would be easier to use different wallets/devices for broadcasting

[pciccioni]

This feature is really important that it is implemented