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python实现openssl的EVP_BytesToKey及AES_256_CBC加解密算法

news 2025/7/6 0:55:29

python实现openssl
EVP_BytesToKey(EVP_aes_256_cbc(), EVP_md5(), NULL, pass, passlen, 1, key, iv);
并实现AES 256 CBC加解密.

# encoding:utf-8import base64
from Crypto.Cipher import AES
from Crypto import Random
from hashlib import md5def EVP_BytesToKey(password, salt, key_len, iv_len):"""实现opensslEVP_BytesToKey(EVP_aes_256_cbc(), EVP_md5(), NULL, pass, passlen, 1, key, iv);"""pass_salt = (password + salt).encode(encoding='utf-8') #传给hashlib.md5前要先转成bytesdtot = md5(pass_salt).digest() # 返回bytes,不要转成十六进制字符串d = [ dtot ]while len(dtot) != (key_len + iv_len):d.append(md5(d[-1] + pass_salt).digest()) # 在一维列表中，下标为-1表示该元素为列表的最后一项dtot += d[-1]return dtot[:key_len], dtot[key_len:key_len+iv_len]def encryt(string, key, iv):"""加密文本:param string: 待加密文本:param key: 密钥:param iv: 偏移量/初始向量:return: 密文"""cipher = AES.new(key, AES.MODE_CBC, iv)x = AES.block_size - (len(string) % AES.block_size)# 长度不整除16时,需要进行补全, 比如少了3个,就填充3个3if x != 0:string = string + chr(x)*xmsg = cipher.encrypt(string.encode('utf-8'))return msgdef decrypt(en_str, key, iv):"""解密文本:param en_str: 待解密文本:param key: 密钥:param iv: 偏移量/初始向量:return: 解密后的文本"""cipher = AES.new(key, AES.MODE_CBC, iv)msg = cipher.decrypt(en_str)padding_len = msg[len(msg)-1]return msg[0:-padding_len]if __name__ == '__main__':with open('res.json', 'r') as fp:content = fp.readlines() #listtext_16str = ''.join(content) # list to strtext_byte = bytes.fromhex(text_16str) #get bytespassword = "%^%xxxxxx"key, iv = EVP_BytesToKey(password, '', 32, 16)#out = encryt('world', key, iv)print(out.hex())out = decrypt(text_byte, key, iv)print(out.decode('utf-8'))