⭐本专栏主要用python实现密码学中的常用经典算法，例如Vigenere、3DES、RSA、ElGamal、Diffie-Hellman、RSA签名、ElGamal签名、HMAC、哈希算法、列移位、AES等等。
🔥文章和代码已归档至【Github仓库：cryptography-codebase】，需要的朋友们自取。或者公众号【AIShareLab】回复密码学也可获取。
Program : 3DES
In this program, you are required to implement the 3DES algorithm using the provided encrypt and decrypt function of DES. The encrypt and decrypt method of 3DES should also be pure functions, i.e. without side effects.
Your program does the following:
Read a hex string from the console input. The string represents the plaintext bytes as a hex string.
Read a hex string from the console input. The string represents the first key bytes as a hex string.
Read a hex string from the console input. The string represents the second key bytes as a hex string.
Read a hex string from the console input. The string represents the third key bytes as a hex string.
Encrypt the plaintext with the three keys.
Print the ciphertext bytes as a hex string.
Decrypt the ciphertext with the three keys.
Print the plaintext bytes after decryption as a hex string.
Example Input & Output
Input:
8787878787878787133457799bbcdff10e329232ea6d0d73133457799bbcdff1
Output:
e98a0b8e59b3eeb78787878787878787
solution code
from libdes import DES_Encrypt, DES_Decryptdef validate_des_key(key: bytes) -> bool:for keyByte in key:binStr: str = "{0:0>8b}".format(keyByte)if sum([1 if b == '1' else 0 for b in binStr]) % 2 == 0:return Falsereturn Trueif __name__ == '__main__':plaintextHex: str = input('plaintext:')key1Hex: str = input('key1:')if not validate_des_key(bytes.fromhex(key1Hex)):raise Exception('Parity check failed on the key.')key2Hex: str = input('key2:')if not validate_des_key(bytes.fromhex(key2Hex)):raise Exception('Parity check failed on the key.')key3Hex: str = input('key3:')if not validate_des_key(bytes.fromhex(key3Hex)):raise Exception('Parity check failed on the key.')ciphertext1: bytes = DES_Encrypt(bytes.fromhex(plaintextHex),bytes.fromhex(key1Hex),)ciphertext2: bytes = DES_Decrypt(ciphertext1,bytes.fromhex(key2Hex),)ciphertext3: bytes = DES_Encrypt(ciphertext2,bytes.fromhex(key3Hex),)print('ciphertext:', ciphertext3.hex())plaintext3: bytes = DES_Decrypt(ciphertext3,bytes.fromhex(key3Hex),)plaintext2: bytes = DES_Encrypt(plaintext3,bytes.fromhex(key2Hex),)plaintext1: bytes = DES_Decrypt(plaintext2,bytes.fromhex(key1Hex),)print('plaintext:', plaintext1.hex())
output
plaintext:8787878787878787key1:133457799bbcdff1key2:0e329232ea6d0d73key3:133457799bbcdff1ciphertext: e98a0b8e59b3eeb7plaintext: 8787878787878787进程已结束，退出代码为 0
