Posts for tag crypto

• [KalmarCTF 2024] Breakfaest

  Robin Jadoul

  Mar 18, 2024

  vole-in-the-head, crypto, zero-knowledge, fiat-shamir

  I heard that you could use VOLE-in-the-head to make post-quantum signatures. Here's a signature scheme based on the Poseidon hash function. Can you create a forgery?

• [GCTF 2022] Cycling

  Robin Jadoul

  Jul 05, 2022

  gctf, organizers, crypto, RSA, factoring

  Pack out your quantum computer and perform 2^1025-3 encryptions to solve this challenge. Good luck doing this in 48h.

• [SECCON CTF 2021] Sign Wars

  Robin Jadoul

  Dec 13, 2021

  seccon, organizers, crypto, ECDSA, lattice, mt19937

  A long time ago in a galaxy far, far away....

• [ictf Apr 2021] My challenges

  Robin Jadoul

  May 01, 2021

  ImaginaryCTF, challenges, crypto, misc, pyjail, web, reversing
• [ictf Mar 2021] My challenges

  Robin Jadoul

  Apr 01, 2021

  ImaginaryCTF, challenges, crypto, misc, pyjail
• Factoring in logarithmic time: a mathemagic trick

  Robin Jadoul

  Jan 22, 2021

  RSA, crypto, fun

  Debunking crackpot claims for fun and profit

• [pbctf 2020] LeaK

  Robin Jadoul

  Dec 07, 2020

  pbctf, organizers, crypto, EHNP, ECDSA, nonce

  I know there's a famous attack on biased nonces. Then, how about this?

• [pbctf 2020] Queensarah2

  Robin Jadoul

  Dec 07, 2020

  pbctf, organizers, crypto, symmetric, cryptanalysis

  The secret mainframe for a distributed hacker group has been discovered. We have managed to exfiltrate some of the code that it runs, but we don't have a physical copy of their access badges. Can you still get the flag?

• [Donjon CTF 2020] BLS Signatures and Secret RNG

  Robin Jadoul

  Nov 23, 2020

  donjon ctf, cryptohackers, crypto, ECC, signatures, ECC
• [Halloween crypto puzzles] Jed

  Robin_Jadoul

  Oct 06, 2018

  crypto, puzzle, halloween
• [IceCTF 2018] Posted

  Robin Jadoul

  Sep 22, 2018

  IceCTF, crypto