This final project for ECE6745 aims to demonstrate algebraic attacks on a 32 bit block cipher circuit through Grobner Basis techniques.

converter.cpp This file converts ASCII input to polynomial representation. block_cipher.lib This file contains functions that convert plaintext to ciphertext. Full_Block_Cipher.sing This file generates the Grobner basis for the given block cipher with an input of plaintext and a key.

STEP1: Compile converter.cpp using the following command:

g++ converter.cpp -o convert

STEP2: In Full_Block_Cipher.sing

2a. Set the cipher text on line 56, position 46. (Limit 4 characters) 2b. Set the key on line 63, position 38. (Limit 4 characters)

STEP3: Execute Full_Block_Cipher.sing in Singular

STEP1. In Singular, execute the command:

G; // Look for elements containing key bits (k_[0:3]) and take note

STEP2. In Singular, execute the command:

fact_list(G); // Returns factored univariate members of the GB

STEP3. Evaluate key polynomials

STEP4. Test recovered key solution to see if you get the same ciphertext given the same plaintext input.