Cryptanalysis Cryptanalysis

Break encryption algorithms

These tests will allow you to hone your cryptography skills. You will be faced with an encoded data. The challenge is to find the type of encoding or encryption and revert it back to find the solution.

Prerequisites:

 Knowledge of most common encoding formats.
 Knowledge of most common hash algorithms and ciphers.
 Knowledge of a scripting language.

challenges 75 Challenges

Results Name Validations Number of points  Explanation for the scores Difficulty  Difficulty Author Note  Notation Solution Date
pas_valide Encoding - UU 20% 73591 5 g0uZ 10 7 October 2006
pas_valide Hash - Message Digest 5 17% 63589 5 g0uZ 7 31 January 2010
pas_valide File - PKZIP 4% 13846 15 g0uZ 6 30 August 2010
pas_valide RSA - Factorisation 2% 5281 25 HacKSpider 5 12 September 2010
pas_valide Known plaintext - XOR 3% 9783 20 Ryscrow 5 3 February 2011
pas_valide Pixel Madness 5% 16921 15 Ryscrow 10 3 February 2011
pas_valide Shift cipher 6% 21850 10 m31z0nyx 10 16 February 2011
pas_valide Monoalphabetic substitution - Caesar 5% 17574 15 Arod 5 22 October 2011
pas_valide Polyalphabetic substitution - Vigenère 3% 10922 20 Arod 3 26 October 2011
pas_valide Monoalphabetic substitution - Polybe 2% 4097 25 koma 6 6 December 2011
pas_valide File - Insecure storage 1 3% 9650 20 g0uZ 7 6 February 2012
pas_valide ELF64 - PID encryption 3% 8448 15 Lu33Y 10 8 February 2012
pas_valide Hash - SHA-2 9% 33646 5 koma 4 3 June 2012
pas_valide Service - CBC Padding 1% 1431 60 koma 2 4 October 2012
pas_valide Service - Timing attack 1% 3004 25 g0uZ , koma 5 28 October 2012
pas_valide Encoding - ASCII 26% 95906 5 Xartrick 10 4 December 2012
pas_valide Code - Pseudo Random Number Generator 2% 3910 20 Tosh 6 19 December 2012
pas_valide System - Android lock pattern 2% 7236 20 Silentd 5 23 December 2012
pas_valide Polyalphabetic substitution - One Time Pad 1% 415 60 Thanat0s 0 2 June 2013
pas_valide Transposition - Rail Fence 2% 6839 20 YellowS4 4 6 April 2014
pas_valide Discrete logarithm problem 1% 1391 40 RFC4949 3 8 June 2014
pas_valide Service - Hash length extension attack 1% 1223 30 koma 1 19 August 2015
pas_valide Initialisation Vector 1% 2394 25 manticore , notfound404 6 25 August 2015
pas_valide AES128 - CTR 1% 788 40 Tosh 2 28 August 2015
pas_valide RSA - Continued fractions 1% 1604 30 sambecks 1 8 September 2015
pas_valide RSA - Multiple recipients 1% 1720 40 franb 4 29 November 2015
pas_valide AES - ECB 1% 2870 25 cez40 4 29 November 2015
pas_valide GEDEFU 1% 594 30 makhno 1 13 September 2016
pas_valide RSA - Padding 1% 311 35 Tosh 0 9 October 2016
pas_valide Enigma Machine 1% 285 50 peyman 2 12 October 2016
pas_valide ECDHE 1% 262 60 Tosh 2 20 November 2016
pas_valide Hash - SHA-3 1% 196 75 Revenger 1 10 December 2016
pas_valide RSA - Common modulus 1% 2169 30 franb 3 24 December 2016
pas_valide RSA - Decipher Oracle 1% 2180 25 Zweisamkeit 4 11 May 2017
pas_valide LFSR - Known plaintext 1% 1187 25 Brissouille 2 28 November 2017
pas_valide RSA - Corrupted key 1 1% 473 30 blackndoor 2 28 November 2017
pas_valide RSA - Corrupted key 2 1% 346 40 blackndoor 1 11 January 2018
pas_valide AES - CBC - Bit-Flipping Attack 1% 1745 25 Tie21 5 17 June 2018
pas_valide AES - Weaker variant 1% 170 70 Cryptanalyse 1 29 August 2018
pas_valide AES - 4 Rounds 1% 395 35 Cryptanalyse 0 5 September 2018
pas_valide AES - Fault attack #1 1% 228 50 Cryptanalyse 1 20 September 2018
pas_valide AES - Fault attack #2 1% 159 80 Cryptanalyse 1 20 September 2018
pas_valide White-Box Cryptography 1% 282 60 Cryptanalyse 3 21 October 2018
pas_valide AES-PMAC 1% 44 100 Cryptanalyse 0 26 May 2019
pas_valide RSA - Corrupted key 3 1% 205 40 blackndoor 0 5 September 2019
pas_valide ECDSA - Introduction 1% 369 35 Jrmbt 2 22 September 2019
pas_valide ECDSA - Implementation error 1% 73 100 Tosh 0 29 September 2019
pas_valide RSA - Lee cooper 1% 178 60 blackndoor , Synacktiv 1 7 November 2019
pas_valide RSA - Signature 1% 235 35 sar 1 9 March 2020
pas_valide Twisted secret 1% 576 25 NonStandardModel 2 14 August 2020
pas_valide OTP - Implementation error 1% 535 30 Podalirius 3 22 March 2021
pas_valide CISCO - Salted Password 2% 6090 10 Tidusrose 3 13 July 2021
pas_valide Hash - DCC2 3% 8802 5 Podalirius 1 13 July 2021
pas_valide Hash - DCC 3% 9636 5 Podalirius 1 13 July 2021
pas_valide Hash - LM 3% 9269 5 Podalirius 2 13 July 2021
pas_valide Hash - NT 2% 7510 5 Podalirius 2 13 July 2021
pas_valide PHP - mt_rand 1% 190 40 NonStandardModel 0 28 March 2022
pas_valide FEAL - Differential Cryptanalysis 1% 53 50 Tosh 1 28 March 2022
pas_valide Side Channel - AES : first round 1% 112 60 walafc0 0 28 March 2022
pas_valide Side Channel - AES : CPA 1% 111 50 cb34 0 28 March 2022
pas_valide RSA - H-rabin 1% 103 60 Vozec 0 21 March 2023
pas_valide Hill Cipher 1% 293 30 LetMeR00t 1 21 March 2023
pas_valide Circular Bit Shift 1% 2011 20 BlackRaven 3 21 March 2023
pas_valide Encoding - Codebook 1% 533 20 n3rada 1 21 March 2023
pas_valide Shamir Secret Sharing - Traitor 1% 125 35 Vozec 1 5 February 2024
pas_valide Shamir Secret Sharing - Reduction 1% 67 70 Vozec 0 5 February 2024
pas_valide Shamir Secret Sharing - Irreducible ? 1% 49 90 Mister7F 1 5 February 2024
pas_valide Shamir Secret Sharing - Introduction 1% 424 30 Vozec 2 5 February 2024
pas_valide AES - ECB - Copy Paste 1% 405 25 Vozec 1 5 February 2024
pas_valide File - PKZIP 2 1% 460 20 kevin.mille 2 8 November 2024
pas_valide DSA - Implementation error 1% 146 25 Vozec 1 13 December 2024
pas_valide ElGamal - Fault attack (Introduction) 1% 72 35 Vozec 0 13 December 2024
pas_valide Goldreich Goldwasser Halevi | Weak Parameter 1% 34 50 Vozec 0 13 December 2024
pas_valide NTRU | Weak Parameter 1% 33 60 Vozec 0 13 December 2024
pas_valide NTRU | Multiple Transmission 1% 40 60 Vozec 0 13 December 2024

Challenge Results Challenge Results

Pseudo Challenge Lang Date
nerzee Cryptanalyse  Encodage - ASCII fr 12 December 2025 at 07:59
ctfdiary Cryptanalysis  CISCO - Salted Password en 12 December 2025 at 03:21
Tchoupi_Gang Cryptanalyse  Circular Bit Shift fr 12 December 2025 at 01:58
AllTx Cryptanalyse  RSA - Padding fr 12 December 2025 at 01:36
LinuxTrimind Cryptanalyse  Encodage - UU fr 12 December 2025 at 00:29
LinuxTrimind Cryptanalyse  Encodage - ASCII fr 12 December 2025 at 00:28
LaGelee Cryptanalyse  Décomposition pixelisée fr 11 December 2025 at 23:30
LaGelee Cryptanalyse  Circular Bit Shift fr 11 December 2025 at 23:28
lol Cryptanalyse  Encodage - ASCII fr 11 December 2025 at 23:27
ethicxz Cryptanalyse  ECDHE fr 11 December 2025 at 23:03