QPC-github

A Bitcoin NFT system

Note: this proposal needs to be slighltly modified since the storage limit for OP_RETURN is 80B and does not work for all cases, but the principles will remain the same and other storage solutions exist, see https://lists.linuxfoundation.org/pipermail/bitcoin-dev/2023-February/021398.html

Then for now some transactions mentionned in that proposal are not standard (ie not relayed by the nodes) but valid (ie a miner can include them into a block)

So, after discussion with the bictoin community, see Allow several OP_RETURN in one tx and no limited size

In case this change, which looks to be admitted by the majority, is trivial and not even a soft fork, is not implemented then please see the different workarounds at the end of this proposal

QPC-github

This has been moved to https://github.com/shaolinfry/bips/blob/bip-uavb-strong/bip-uaversionbits-strong.mediawiki

QPC-github

This has been moved to https://github.com/bitcoin/bips/blob/master/bip-0148.mediawiki

QPC-github

# Raw transaction API example work-through
# Send coins to a 2-of-3 multisig, then spend them.
#
# For this example, I'm using these three keypairs (public/private)
# 0491bba2510912a5bd37da1fb5b1673010e43d2c6d812c514e91bfa9f2eb129e1c183329db55bd868e209aac2fbc02cb33d98fe74bf23f0c235d6126b1d8334f86 / 5JaTXbAUmfPYZFRwrYaALK48fN6sFJp4rHqq2QSXs8ucfpE4yQU
# 04865c40293a680cb9c020e7b1e106d8c1916d3cef99aa431a56d253e69256dac09ef122b1a986818a7cb624532f062c1d1f8722084861c5c3291ccffef4ec6874 / 5Jb7fCeh1Wtm4yBBg3q3XbT6B525i17kVhy3vMC9AqfR6FH2qGk
# 048d2455d2403e08708fc1f556002f1b6cd83f992d085097f9974ab08a28838f07896fbab08f39495e15fa6fad6edbfb1e754e35fa1c7844c41f322a1863d46213 / 5JFjmGo5Fww9p8gvx48qBYDJNAzR9pmH5S389axMtDyPT8ddqmw

# First: combine the three keys into a multisig address:
./bitcoind createmultisig 2 '["0491bba2510912a5bd37da1fb5b1673010e43d2c6d812c514e91bfa9f2eb129e1c183329db55bd868e209aac2fbc02cb33d98fe74bf23f0c235d6126b1d8334f86","04865c40293a680cb9c020e7b1e106d8c1916d3cef99aa431a56d253e69256dac09ef122b1a9

QPC-github

Described here is a variant of what has previously been published under the name "P2EP" or Pay-to-endpoint, in which A pays B but B contributes utxos, i.e. it's a coinjoin-payment.

I'm using the term "payjoin" here to refer to using that idea, but not including a URI/endpoint specific to B, and not allowing (as a merchant would) arbitrary payments, which opens up certain problems around snooping attackers (more on this below). So payjoin just means "A pays B but B actively participates and passes across utxos as extra inputs".

I'll defer a more features-focused and non-tech friendly description of what this means to a later blogpost.

QPC-github

# Replaced with this: https://github.com/AdamISZ/3roundmusig4fun

QPC-github

Chaumian cash in a Bitcoin world - cashu, Fedimint

What's this for?

• More scalable/faster than a blockchain (not enough utxos)
• Much better privacy security model than a blockchain
• Same or better theft security model than TTP but much worse than a blockchain

If it's so great, why hasn't it been done yet?

QPC-github

#!/usr/bin/env python
help = """
A demonstration of the algorithm of
the linkable ring signature algorithm in Goodall and Noether's
Triptych:
https://eprint.iacr.org/2020/018

To use, specify two arguments: n (integer) and m (integer), such
that N (size of ring) = n^m.

QPC-github

#!/usr/bin/env python
help = """
A demonstration of the algorithm of:
Groth and Kohlweiss 2014 "How to leak a secret and spend a coin."
https://eprint.iacr.org/2014/764.pdf

This uses the Joinmarket bitcoin backend, mostly just for its encapsulation
of the package python-bitcointx (`pip install bitcointx` or github:
https://github.com/Simplexum/python-bitcointx).

QPC-github

RIDDLE

Due to unexpected failures of github's LaTeX parsing (which were not evident until I published this, but have persisted afterwards), and since the mathematical parts are important in this, I have migrated this proposal to a blog post with identical content, but correctly formatted equations.

Please continue to put any comments here.