46 lines
1.7 KiB
Python
46 lines
1.7 KiB
Python
import Crypto, base64
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from Crypto.Cipher import PKCS1_v1_5
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from Crypto.PublicKey import RSA
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from Crypto.Cipher import DES
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# rsa解密密文方法
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def get_max_length(rsa_key, encrypt=True):
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"""加密内容过长时 需要分段加密 换算每一段的长度.
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:param rsa_key: 钥匙.
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:param encrypt: 是否是加密.
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"""
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blocksize = Crypto.Util.number.size(rsa_key.n) / 8
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reserve_size = 11 # 预留位为11
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if not encrypt: # 解密时不需要考虑预留位
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reserve_size = 0
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maxlength = blocksize - reserve_size
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return maxlength
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# ------------------------解密密文------------------------
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def decryption(text_encrypted_base64: str, private_key: bytes):
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# 字符串指定编码（转为bytes）
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text_encrypted_base64 = text_encrypted_base64.encode('utf-8')
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# base64解码
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text_encrypted = base64.b64decode(text_encrypted_base64)
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# 构建私钥对象
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private_key = RSA.importKey(private_key)
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max_length = int(get_max_length(private_key, False))
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cipher_private = PKCS1_v1_5.new(private_key)
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length = len(text_encrypted)
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if length < max_length:
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return b''.join(cipher_private.decrypt(text_encrypted, b'xyz'))
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# 需要分段
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offset = 0
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res = []
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while length - offset > 0:
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if length - offset > max_length:
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res.append(cipher_private.decrypt(text_encrypted[offset:offset + max_length], b'xyz'))
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else:
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res.append(cipher_private.decrypt(text_encrypted[offset:], b'xyz'))
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offset += max_length
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text_decrypted = b''
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for i in res:
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text_decrypted += i
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# print(text_decrypted.decode())
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return text_decrypted.decode()
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