niooss-ledger

Short write-up for RWPQC CTF 2024

Subject: https://github.com/sandbox-quantum/CTF-RWPQC2024/tree/ea398c3e934cdb35198c4efa180fa6bd6e2f9670

Challenge 1

As the secret key $s$ is only 32-bit long, it is possible to brute-force it. As $t_1 = A_1 * s_1 + A_2 * s_2 + e$ with $e$ some error polynomials, we can speed things up by splitting the brute-force in two 16-bit enumerations with $s_1$ and $s_2$ and comparing $A_1 * s_1$ with $t_1 - A_2 * s_2$. If these two polynomials have coefficients which only differ by one, $(s_1, s_2)$ is likely to be the secret key.

niooss-ledger

Write-up for ZK Hack IV puzzle F3: Chaos Theory

• Author: Nicolas IOOSS
• Date: 2024-01-30
• Puzzle: https://zkhack.dev/zkhackIV/puzzleF3.html, https://github.com/ZK-Hack/puzzle-chaos-theory

1. Subject

Bob designed a new one time scheme, that's based on the tried and true method of

niooss-ledger

Write-up for ZK Hack IV puzzle F2: Supervillain

• Author: Nicolas IOOSS
• Date: 2024-01-24
• Puzzle: https://zkhack.dev/zkhackIV/puzzleF2.html, https://github.com/ZK-Hack/puzzle-supervillain

1. Subject

Bob has been designing a new optimized signature scheme for his L1 based on BLS signatures.

niooss-ledger

Write-up for ZK Hack IV puzzle F1: Gamma Ray

• Author: Nicolas IOOSS
• Date: 2024-01-18
• Puzzle: https://zkhack.dev/zkhackIV/puzzleF1.html, https://github.com/ZK-Hack/puzzle-gamma-ray

1. Subject

Bob was deeply inspired by the Zcash design [1] for private transactions and had

niooss-ledger

Write-up for ZK Hack III puzzle #3: Bigger is Better

• Author: Nicolas IOOSS
• Date: 2022-12-12
• Puzzle: https://zkhack.dev/zkhackIII/puzzleT3.html, https://github.com/ZK-Hack/puzzle-bigger-is-better

1. Subject

The GitHub repository contains this introduction.

niooss-ledger

Write-up for ZK Hack III puzzle #2: Power corrupts

• Author: Nicolas IOOSS
• Date: 2022-12-05
• Puzzle: https://zkhack.dev/zkhackIII/puzzleT2.html, https://github.com/ZK-Hack/puzzle-power-corrupts

1. Subject

The GitHub repository contains this introduction.

niooss-ledger

Write-up for ZK Hack III puzzle #1: Zero-Sum Game

• Author: Nicolas IOOSS
• Date: 2022-11-25
• Puzzle: https://zkhack.dev/zkhackIII/puzzleT1.html, https://github.com/ZK-Hack/puzzle-zero-sum-game

1. Subject

Bob has designed a new private payments protocol design, where every note comes with a secret

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

niooss-ledger

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. >

niooss-ledger

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.