cryptopals challenges

Todo

• Make unhex function accept hex chars only (0-9, A-F)
• Make single error system

Done

1.1 Convert hex to base64
1.2 Fixed XOR
1.3 Single-byte XOR cipher
1.4 Detect single-charackter XOR
1.5 Implement repeating-key XOR
1.6 Break repeating-key XOR
1.7 AES in ECB mode