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| #!/usr/bin/env python3.8 | |
| # -*- coding: UTF-8 -*- | |
| import binascii | |
| from flask import Flask | |
| from flask import request | |
| from Crypto.Cipher import DES | |
| webapp = Flask(__name__) | |
| KEY = "qwerasdf" | |
| IV = "AAAABBBB" | |
| BLOCK_SIZE = DES.block_size | |
| U8 = "utf-8" | |
| U8 = "ASCII" | |
| def PAD(s): return s + (BLOCK_SIZE - len(s) % | |
| BLOCK_SIZE) * chr(BLOCK_SIZE - len(s) % BLOCK_SIZE) | |
| def UNPAD(s): return s[0:-ord(s[-1])] | |
| def UNPAD_BYTES(s): return s[0:-s[-1]] | |
| TO_BYTES = lambda s: s.encode(U8) | |
| TO_STR = lambda s: s.decode(U8) | |
| STR2HEX = lambda s: binascii.hexlify(TO_BYTES(s)) | |
| def check_pad(plain: bytes): | |
| if len(plain) > 8: | |
| plain = plain[-8:] | |
| p = plain[-1] | |
| if (p > 8) or p == 0: | |
| return False | |
| for i in range(1, p+1): | |
| if plain[8 - i] != p: | |
| return False | |
| return True | |
| @webapp.route("/") | |
| def hello_world(): | |
| return "Hello World!" | |
| @webapp.route("/encrypt") | |
| def encrypt(): | |
| cipher_handler = DES.new(key=KEY, mode=DES.MODE_CBC, IV=IV) | |
| plain_text: str = request.args.get("plain_text") | |
| print("Plain text:", plain_text) | |
| padded_plain_text: str = PAD(plain_text) | |
| print("After pad:", padded_plain_text, " => ", STR2HEX(padded_plain_text)) | |
| cipher: bytes = cipher_handler.encrypt(padded_plain_text) | |
| hex_cipher = binascii.hexlify(cipher) | |
| print("Hex cipher:", hex_cipher) | |
| return binascii.hexlify(TO_BYTES(IV)) + hex_cipher | |
| @webapp.route("/decrypt") | |
| def decrypt(): | |
| cipher_text: str = request.args.get("cipher_text") | |
| print("IV + cipher:", cipher_text) | |
| cipher: bytes = binascii.unhexlify(cipher_text) | |
| iv = cipher[:8] | |
| cipher = cipher[8:] | |
| print("iv:", binascii.hexlify(iv), " ,cipher:", binascii.hexlify(cipher)) | |
| handler = DES.new(key=KEY, mode=DES.MODE_CBC, IV=iv) | |
| plain = handler.decrypt(cipher) | |
| print("plain with pad:", binascii.hexlify(plain)) | |
| if not check_pad(plain): | |
| return "Error pad!" | |
| plain_text = UNPAD_BYTES(plain) | |
| print("plain after unpad:", binascii.hexlify(plain_text)) | |
| # 第一次使用的 | |
| # if plain_text != b"nnnn": | |
| # return "Error key!" | |
| # 第二次使用的 | |
| if plain_text != b"lightless_233": | |
| return "Error key!" | |
| else: | |
| return b"Corrent key! " + plain_text | |
| return plain_text |
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