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.

 50 Challenges

Results Name Validations Number of points  Explanation for the scores Difficulty  Difficulty Author Note  Notation Solution
pas_valide ECDSA - Implementation error 1% 22 100 Tosh 0
pas_valide Polyalphabetic substitution - One Time Pad 1% 306 60 Thanat0s 0
pas_valide AES - 4 Rounds 1% 169 35 Cryptanalyse 0
pas_valide RSA - Padding 1% 184 35 Tosh 0
pas_valide RSA - Corrupted key 2 1% 160 40 blackndoor 0
pas_valide RSA - Corrupted key 3 1% 80 40 blackndoor 0
pas_valide AES-PMAC 1% 12 100 Cryptanalyse 0
pas_valide AES - Weaker variant 1% 77 70 Cryptanalyse 1
pas_valide Service - CBC Padding 1% 833 60 koma 1
pas_valide Twisted secret 1% 134 25 NonStandardModel 1
pas_valide Service - Hash length extension attack 1% 644 30 koma 1
pas_valide LFSR - Known plaintext 1% 510 25 Brissouille 1
pas_valide AES - Fault attack #2 1% 67 80 Cryptanalyse 1
pas_valide RSA - Signature 1% 74 35 s4r 1
pas_valide Hash - SHA-3 1% 86 75 Revenger 1
pas_valide GEDEFU 1% 416 30 makhno 1
pas_valide AES - Fault attack #1 1% 91 50 Cryptanalyse 1
pas_valide RSA - Lee cooper 1% 74 60 blackndoor, Synacktiv 1
pas_valide RSA - Continued fractions 1% 951 30 sambecks 1
pas_valide AES128 - CTR 1% 478 40 Tosh 2
pas_valide ECDSA - Introduction 1% 141 35 Jrmbt 2
pas_valide Enigma Machine 1% 157 50 peyman 2
pas_valide ECDHE 1% 153 60 Tosh 2
pas_valide RSA - Common modulus 1% 1024 30 franb 2
pas_valide RSA - Corrupted key 1 1% 240 30 blackndoor 2
pas_valide AES - CBC - Bit-Flipping Attack 1% 754 25 Tie21 2
pas_valide RSA - Multiple recipients 1% 852 40 franb 3
pas_valide Transposition - Rail Fence 2% 4033 20 YellowS4 3
pas_valide White-Box Cryptography 1% 117 60 Cryptanalyse 3
pas_valide RSA - Decipher Oracle 1% 963 25 Zweisamkeit 3
pas_valide Polyalphabetic substitution - Vigenère 4% 6606 20 Arod 3
pas_valide Discrete logarithm problem 1% 702 40 Thanat0s, RFC4949 3
pas_valide Monoalphabetic substitution - Caesar 5% 9973 15 Arod 4
pas_valide System - Android lock pattern 3% 4359 20 Silentd 4
pas_valide AES - ECB 1% 1677 25 cez40 4
pas_valide Service - Timing attack 1% 1861 25 g0uZ, koma 4
pas_valide Hash - SHA-2 11% 21984 5 koma 4
pas_valide RSA - Factorisation 2% 2822 25 HacKSpider 5
pas_valide Initialisation Vector 1% 1278 25 manticore, notfound404 5
pas_valide Code - Pseudo Random Number Generator 2% 2320 20 Tosh 5
pas_valide Known plaintext - XOR 3% 5962 20 Ryscrow 5
pas_valide File - Insecure storage 1 3% 6223 20 g0uZ 6
pas_valide File - PKZIP 4% 7899 15 g0uZ 6
pas_valide Hash - Message Digest 5 21% 42687 5 g0uZ 6
pas_valide Monoalphabetic substitution - Polybe 2% 2348 25 koma 6
pas_valide Shift cipher 7% 13415 10 m31z0nyx 9
pas_valide Encoding - UU 21% 42364 5 g0uZ 10
pas_valide Pixel Madness 6% 10524 15 Ryscrow 10
pas_valide ELF64 - PID encryption 3% 5595 15 Lu33Y 10
pas_valide Encoding - ASCII 26% 54055 5 Xartrick 10

Challenge Results Challenge Results

Pseudo Challenge Lang date
EF115_bmkiet   Hash - Message Digest 5 25 February 2021 at 14:11
EF115_bmkiet   Encoding - UU 25 February 2021 at 14:04
as_excube   Encodage - ASCII 25 February 2021 at 13:59
EF115_bmkiet   Encoding - ASCII 25 February 2021 at 13:54
tobi   Encodage - UU 25 February 2021 at 13:53
nedStark   Encoding - ASCII 25 February 2021 at 13:25
Kakyoin54   Substitution monoalphabétique - César 25 February 2021 at 13:25
LucasVal2B   Encodage - UU 25 February 2021 at 13:00
duine-eigin   Monoalphabetic substitution - Caesar 25 February 2021 at 12:48
tobi   Encodage - ASCII 25 February 2021 at 12:37