Crypto Challenge Set 1

1. Convert hex to base64

• DIY base64 tool in new soln
• (deprecated) run : c++ -std=c++2a -lssl -lcrypto _.cc && ./a.out

2. Fixed XOR

• added new solution in cc

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