Python 코드에 대해서 질문하려고 합니다.

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def simpleDES(key, message, mode): translated &#61; '' for sym in message: if mode &#61;&#61; 'encrypt': encMsg &#61; encrypt(key, ord(sym)) translated &#61; translated &#43; chr(encMsg) if mode &#61;&#61; 'decrypt': decMsg &#61; decrypt(key, ord(sym)) translated &#61; translated &#43; chr(decMsg) return translated def simpleDES_CBC(key, message, mode, IV): translated &#61; '' prev &#61; IV for sym in message: if mode &#61;&#61; 'encrypt': encMsg &#61; encrypt(key, ord(sym) ^ prev) ## ord(sym) ^ prev 이건 XOR연산 prev &#61; encMsg translated &#61; translated &#43; chr(encMsg) if mode &#61;&#61; 'decrypt': decMsg &#61; decrypt(key, ord(sym)) ^ prev ##(prev는 전의 ciphertext역할) prev &#61; ord(sym) translated &#61; translated &#43; chr(decMsg) return translated def simpleDES_CFB(key, message, mode, IV): # implement ... return def simpleDES_OFB(key, message, IV): # implement ... return def simpleDES_CTR(key, message, nonce): # implement ... return if __name__ &#61;&#61; &#34;__main__&#34;: message &#61; &#34;aaaabbbbccccdddd&#34; message1 &#61; &#34;jun min-jae&#34; print(&#34;message :&#34;, message) # A반 print(&#34;A반 : Simplified DES with ECB/CBC/CFB/OFB/CTR Mode&#34;) key &#61; 0b1111100000 IV &#61; 0b01010101 # B반 print(&#34;B반 : Simplified DES with ECB/CBC/CFB/OFB/CTR Mode&#34;) key &#61; 0b0000011111 IV &#61; 0b10101010 nonce &#61; 0b11110000 print(&#34;Key :&#34;, bin(key)) print(&#34;IV :&#34;, bin(IV)) print(&#34;nonce :&#34;, bin(nonce)) print() encrypt_ebc &#61; simpleDES(key, message, &#34;encrypt&#34;) decrypt_ebc &#61; simpleDES(key, encrypt_ebc, &#34;decrypt&#34;) print(&#34;Message encrypted by EBC :&#34;, encrypt_ebc) print(&#34;Message decrypted by EBC :&#34;, decrypt_ebc) print() encrypt_cbc &#61; simpleDES_CBC(key, message, &#34;encrypt&#34;, IV) decrypt_cbc &#61; simpleDES_CBC(key, encrypt_cbc, &#34;decrypt&#34;, IV) print(&#34;Message encrypted by CBC :&#34;, encrypt_cbc) print(&#34;Message decrypted by CBC :&#34;, decrypt_cbc) print() encrypt_ofb &#61; simpleDES_OFB(key, message, IV) decrypt_ofb &#61; simpleDES_OFB(key, encrypt_ofb, IV) print(&#34;Message encrypted by OFB :&#34;, encrypt_ofb) print(&#34;Message decrypted by OFB :&#34;, decrypt_ofb) print() encrypt_cfb &#61; simpleDES_CFB(key, message, &#34;encrypt&#34;, IV) print(&#34;Message encrypted by CFB :&#34;, encrypt_cfb) decrypt_cfb &#61; simpleDES_CFB(key, encrypt_cfb, &#34;decrypt&#34;, IV) print(&#34;Message decrypted by CFB :&#34;, decrypt_cfb) print() encrypt_ctr &#61; simpleDES_CTR(key, message, nonce) decrypt_ctr &#61; simpleDES_CTR(key, encrypt_ctr, nonce) print(&#34;Message encrypted by CTR :&#34;, encrypt_ctr) print(&#34;Message decrypted by CTR :&#34;, decrypt_ctr)위에는 각각 DES, CBC, CFB, OFB, CTR에 대한 코드를 만들어야 합니다.DES와 CBC에 대한 코드는 주셨고 CFB, OFB, CTR에 대한 코드를 만드는 것이 과제입니다.그중에 CFB에 해당하는 코드를 제 나름대로 해석해서 def simpleDES_CFB(key, message, mode, IV):# implement ... translated &#61; '' prev &#61; IV for sym in message: if mode &#61;&#61; 'encrypt': encMsg &#61; encrypt(key, IV) ciphertext &#61; encMsg ^ ord(sym) prev &#61; ciphertext translated &#61; translated &#43; chr(encMsg) if mode &#61;&#61; 'decrypt': decMsg &#61; encrypt(key, IV) ^ prev##(ciphertext) prev &#61; ord(sym) translated &#61; translated &#43; chr(decMsg) return translated

Python 코드에 대해서 질문하려고 합니다.

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