from cryptography_s_des_exploring.sdes.keys import generate_subkeys from cryptography_s_des_exploring.sdes.sdes import apply_table, function, IP, s0, expansion, s1, IP_inv from cryptography_s_des_exploring.sdes.blocks import encode, encode_bytes def encrypt_block(key: str, block: str): """ Encrypt the 8-bit block with 10-bit key. key is a binary which represented with a 10 character string. block is a binary which represented with 8 character string. """ key1, key2 = generate_subkeys(key) temp = apply_table(block, IP) temp = function(expansion, s0, s1, key1, temp) temp = temp[4:] + temp[:4] temp = function(expansion, s0, s1, key2, temp) ciphertext = apply_table(temp, IP_inv) return ciphertext def encrypt(key: str, message: str): """ Encrypt the message with the 10-bit key. The message is split into 8-bit blocks. key is a binary which represented with a 10 character string. """ encoded = encode(message) encrypted = list(map(lambda b: encrypt_block(key, b), encoded)) return encode_bytes(encrypted)