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std::string AESSha1Prng::aesDecrypt(const std::string &ciphertext, std::string key) {
//处理java SHA1PRNG密钥 两次sha1后截取前32。。。。。
std::string output;
while (output.size() < 16) { //16对应32
CryptoPP::byte hash[CryptoPP::SHA1::DIGESTSIZE];
CryptoPP::SHA1().CalculateDigest(hash, (CryptoPP::byte *) key.data(), key.size());
key.assign((char *) hash, CryptoPP::SHA1::DIGESTSIZE);
CryptoPP::SHA1().CalculateDigest(hash, (CryptoPP::byte *) key.data(), key.size());
key.assign((char *) hash, CryptoPP::SHA1::DIGESTSIZE);
output += key;
}
std::string key1 = output.substr(0, 16);
//用处理过的key解密数据
CryptoPP::SecByteBlock aesKey(reinterpret_cast<const CryptoPP::byte *>(key1.data()), key1.size());
CryptoPP::ECB_Mode<CryptoPP::AES>::Decryption decryption;
decryption.SetKey(aesKey, aesKey.size());
std::string decryptedText;
CryptoPP::StringSource stringSource(ciphertext, true,
new CryptoPP::Base64Decoder(
new CryptoPP::StreamTransformationFilter(decryption,
new CryptoPP::StringSink(
decryptedText)
)
)
);
return decryptedText;
}