Nicolas IOOSS niooss-ledger

Write-up for ZK Hack Mini puzzle #1: There's Something in the AIR

Author: Nicolas IOOSS
Date: 2022-03-04
Puzzle: https://www.zkhack.dev/puzzleM1.html, https://github.com/kobigurk/zkhack-there-is-something-in-the-AIR

1. Subject

Alice implemented a Semaphore protocol to collect anonymous votes from her friends on various

Write-up for zkHack puzzle #6: Soundness of Music

Author: Nicolas IOOSS
Date: 2021-12-01
Puzzle: https://www.zkhack.dev/puzzle6.html

Subject

It is a well-known fact that 1+1=2. Recent work by Alice von Trapp (et al) suggests that under special conditions in the Swiss Alps, 1+1+1+1=1. Alice has been unable to prove this statement over the BLS12-381 scalar field. The primary difficulty appears to be the fact that 1 is not equal to 4. Alice's proving system can write a proof for every statement (x,y) where x and y are BLS12-381 scalars, and x+x+x+x=y. The proving system easily outputs a proof for the statement (1,4) showing 1+1+1+1=4, but seems unable to produce a proof for the statement (1,1) showing 1+1+1+1=1. >

Write-up for zkHack puzzle #5: To be Adaptive is to be Strong

Author: Nicolas IOOSS
Date: 2021-11-25
Puzzle: https://www.zkhack.dev/puzzle5.html

1. Subject

Shallan recently found a proof system (see below) that enables proving that two Pedersen commitments commit to the same message (but with potentially different randomness). She employes this in her private cryptocurrency to show that two committed coins have the same value. However, soon after deployment, she receives a message from a self-proclaimed hacker. The message contains two Pedersen commitments and their openings, and a proof of message equality for these commitments. The proof is valid, but there's a twist: the openings contain different messages! How can this be? Reproduce the attack and help Shallan diagnose the problem in her system.

Write-up for zkHack puzzle #4: Hidden in Plain Sight

Author: Nicolas IOOSS
Date: 2021-11-19
Puzzle: https://www.zkhack.dev/puzzle4.html

1. Subject

The puzzle is described in GitHub repository https://github.com/kobigurk/zkhack-hidden-in-plain-sight:

Write-up for zkHack puzzle #3: Double Trouble

Author: Nicolas IOOSS
Date: 2021-11-12
Puzzle: https://www.zkhack.dev/puzzle3.html

1. The data

The puzzle consists in a Rust project available on https://github.com/kobigurk/zkhack-double-trouble. When running it, the following message is displayed:

Write-up for zkHack puzzle #1: zkhack-bls-pedersen

Author: Nicolas IOOSS
Date: 2021-10-27
Puzzle: https://www.zkhack.dev/puzzle1.html
Repository with commit hash: https://github.com/niooss-ledger/zkhack2021-bls-pedersen/tree/288a1d5945d751603510b75fecf522f109670b77

Puzzle

The puzzle consists in a Rust project:

	#!/usr/bin/env python3
	"""Solve zkHack puzzle #2 (https://www.zkhack.dev/puzzle2.html)

	On https://github.com/kobigurk/zkhack-trusted-setup there is a Rust program
	which displays:

	Alice has computed a trusted setup for a Groth16 proof scheme.
	She decided to use a 128-bit long secret, and she swears that she does not
	know the secret s needed to get this setup.
	The trusted setup is constructed as follows using two additional scalars α