Cryptanalysis of 6-round DES

Breaking 6 round DES using chosen plaintext attack.

Follow the instructions to run:

#PHASE 1 : Go to generate_textstring.py #Uncomment the following code to run Phase 1 - generate input pairs #input_pairs()

#PHASE 2 - Run Response.py to get ciphertexts of the input pairs

#PHASE 3 - Uncomment the following lines in generate_textstring.py convert_responsefile_to_cipher() convert_pairs_to_bitstring('c')

#PHASE 4 - compute the input output xors into the sboxes in the last round #Run compute_input_output_xor.py in order to do this

#PHASE 5 - Find key possibilities by running find_key.py

You can see the 30 bit key values in Repeated_cipher_pairs.txt. The one with the maximum frequency are the required key bits.

Name		Name	Last commit message	Last commit date
Latest commit History 88 Commits
Output files		Output files
.DS_Store		.DS_Store
README.md		README.md
Repeated_cipher_pairs.txt		Repeated_cipher_pairs.txt
Request.py		Request.py
boxes.py		boxes.py
boxes.pyc		boxes.pyc
bruteforce.py		bruteforce.py
cipher.txt		cipher.txt
cipherpair.txt		cipherpair.txt
cipherxor.txt		cipherxor.txt
compute_input_output_xor.py		compute_input_output_xor.py
des.py		des.py
des.pyc		des.pyc
des_decryption.py		des_decryption.py
expandr5.txt		expandr5.txt
finalcipher.txt		finalcipher.txt
find_key.py		find_key.py
generate_roundkeys.py		generate_roundkeys.py
generate_roundkeys2.py		generate_roundkeys2.py
generate_textstrings.py		generate_textstrings.py
input.txt		input.txt
inputxor.txt		inputxor.txt
key_scheduling.py		key_scheduling.py
outputxor.txt		outputxor.txt
response.txt		response.txt