AES-128, 192, 256 implementation in C with ISO/IEC 7816-4 standard padding. CBC mode implemented over AES.

1. To use different key length in AES over CBC, use command:

   • gcc -DNk=4 cbc.c // for 128 bit AES keys
   • gcc -DNk=6 cbc.c // for 192 bit AES keys
   • gcc -DNk=8 cbc.c // for 256 bit AES keys

2. The implementation uses following values as default

   • DATA="00112233445566778899aabbccddeeff"
   • KEYS="000102030405060708090a0b0c0d0e0f" //for AES-128
   • KEYS="000102030405060708090a0b0c0d0e0f1011121314151617" //for AES-192
   • KEYS="000102030405060708090a0b0c0d0e0f101112131415161718191a1b1c1d1e1f" //for AES-256

3. cbc.c file uses aes_1.1cbc.c file as a dependency. Make sure to keep them together.

4. The padding added is 10000... all zeros.

5. Example vectors taken from https://nvlpubs.nist.gov/nistpubs/FIPS/NIST.FIPS.197.pdf

6. For gprof check:

   • Uncomment the gprof lines with 100,000 iteratoions in main function and then on terminal type:
     • gcc -Wall -pg aes.c -o aes
     • ./aes
     • gprof aes gmon.out > profile_output