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