adidev-kgp / aes Goto Github PK

1. Playing with inputs and without modifying or looking at the code, try to identify different errors that could occur using the reference implementation given in ref_aes.c

1. With a key of your choice (you can use the one hardcoded), statistically test the quality of the ref_aes.c implementation using it as a random number generator with the dieharder cli. You can inspire/use the code in comments as base of your test.

2. (Bonus) Fixing the AES implementation provided, retry the diehard test to make it pass everything (with 1k samples).

Material:

• https://en.wikipedia.org/wiki/Diehard_tests
• apt-get install dieharder (on MacOS youll need to DL the source and install it manually)
• ref_aes.c
• aes.diehard (pre-formated file)

Using only the SBox look-up table given in ref_aes.c, the following state input of the AES algorithm, and the following internal output taken after the first SubBytes in AES ( ARK + SB done by the algorithm), propose an algorithm that recovers the corresponding round key (round key 0) in a efficient manner.

Material:

• Input: 0xf69f2445, 0xdf4f9b17, 0xad2b417b, 0xe66c3710
• Output (after 1 addroundkey and 1 (proper) subbytes): 0x5DDC4AAF, 0x415C0534, 0x1530EF67, 0x9872021C