Cryptopals

Solutions to the Matasano Cryptography Challenges

Set 1: Basics

1. Convert hex to base64
2. Fixed XOR
3. Single-byte XOR cipher
4. Detect single-character XOR
5. Implement repeating-key XOR
6. Break repeating-key XOR
7. AES in ECB mode
8. Detect AES in ECB mode

Set 2: Block Crypto

9. Implement PKCS#7 padding
10. Implement CBC mode
11. An ECB/CBC detection oracle
12. Byte-at-a-time ECB decryption (Simple)
13. ECB cut-and-paste
14. [Byte-at-a-time ECB decryption (Harder)]
15. PKCS#7 padding validation
16. [CBC bitflipping attacks]

Set 3: Block & Stream Crypto

17. [The CBC padding oracle]
18. [Implement CTR, the stream cipher mode]
19. [Break fixed-nonce CTR mode using substitutions]
20. [Break fixed-nonce CTR statistically]
21. Implement the MT19937 Mersenne Twister RNG
22. Crack an MT19937 seed
23. Clone an MT19937 RNG from its output
24. [Create the MT19937 stream cipher and break it]