Question

我正在写一个基于crypto ++库的类。此类是使用AES算法对数据进行编码和解码的简单方法。这是我的代码：

class AESEncryption
{
public:
    static std::string decrypt(const std::string& data, const std::string& password);
    static std::string encrypt(const std::string& data, const std::string& password);
};
std::string AESEncryption::encrypt(const std::string& data, const std::string& password)
{
    std::vector<CryptoPP::byte> key(password.begin(), password.end());
    std::string result;
    CryptoPP::ECB_Mode<CryptoPP::AES>::Encryption encryption;
    encryption.SetKey(key.data(), key.size());
    CryptoPP::StringSource(data, true, new CryptoPP::StreamTransformationFilter(encryption, new CryptoPP::StringSink(result)));

    return result;
}

std::string AESEncryption::decrypt(const std::string& data, const std::string& password)
{
    std::vector<CryptoPP::byte> key(password.begin(), password.end());
    std::string result;
    CryptoPP::ECB_Mode<CryptoPP::AES>::Decryption decryption;
    decryption.SetKey(key.data(), key.size());
    CryptoPP::StringSource(data, true, new CryptoPP::StreamTransformationFilter(decryption, new CryptoPP::StringSink(result)));
    return result;
}

我开始使用标准fips197（第46页）中的示例测试班级

这是我的测试代码：

namespace
{
    QByteArray key(QByteArray::fromHex("000102030405060708090A0B0C0D0E0F101112131415161718191A1B1C1D1E1F"));
    QByteArray plainText(QByteArray::fromHex("00112233445566778899AABBCCDDEEFF"));
    QByteArray result(QByteArray::fromHex("8EA2B7CA516745BFEAFC49904B496089"));
}

TEST(AESEncrypt, Valid)
{
    std::string key_str(key.begin(), key.end());
    std::string paintText_str(plainText.begin(), plainText.end());
    std::string expected_result(result.begin(), result.end());
    auto result = AESEncryption::encrypt(paintText_str, key_str);
    EXPECT_EQ(result, expected_result);
    auto decrypt = AESEncryption::decrypt(result, key_str);
    EXPECT_EQ(decrypt, paintText_str);
}

我得到了下一个结果：

Expected equality of these values:
  result
    Which is: "\x8E\xA2\xB7\xCAQgE\xBF\xEA\xFCI\x90KI`\x89\x9F;u\x4\x92o\x8B\xD3n1\x18\xE9\x3\xA4\xCDJ"
  expected_result
    Which is: "\x8E\xA2\xB7\xCAQgE\xBF\xEA\xFCI\x90KI`\x89"

我得到了无用的数据：

\x9F;u\x4\x92o\x8B\xD3n1\x18\xE9\x3\xA4\xCDJ

如何解决？加密符合标准的我该怎么办？

Answer 1

Expected equality of these values:
  result
    Which is: "\x8E\xA2\xB7\xCAQgE\xBF\xEA\xFCI\x90KI`\x89\x9F;u\x4\x92o\x8B\xD3n1\x18\xE9\x3\xA4\xCDJ"
  expected_result
    Which is: "\x8E\xA2\xB7\xCAQgE\xBF\xEA\xFCI\x90KI`\x89"

如何解决？加密符合标准的我该怎么办？

提供的FIPS 197 ECB模式测试不带填充。但是，下面的代码使用PKCS填充，由于填充，该填充会增加16个字节：

StringSource(data, true, new StreamTransformationFilter(encryption, new StringSink(result)));

更正确地讲，ECB模式默认使用DEFAULT_PADDING，对于ECB模式和CBC模式则为PKCS_PADDING。我认为您应该改用NO_PADDING：

StringSource(data, true, new StreamTransformationFilter(encryption, new StringSink(result), NO_PADDING));

另请参阅StreamTransformationFilter的文档。这就是您正在使用的过滤器所发生的情况：

StreamTransformationFilter (
    StreamTransformation &c,
    BufferedTransformation *attachment=NULL,
    BlockPaddingScheme padding=DEFAULT_PADDING)

关于“ Crypto ++ AES与标准fips197不匹配” ，您可以使用以下代码通过FIPS 197测试向量（除了SP800-38）测试库：

$ ./cryptest.exe tv aes
Using seed: 1544068124

Testing SymmetricCipher algorithm AES/ECB.
....
Testing SymmetricCipher algorithm AES/CBC.
........
Testing SymmetricCipher algorithm AES/CFB.
.......
Testing SymmetricCipher algorithm AES/OFB.
....
Testing SymmetricCipher algorithm AES/CTR.
.............

Crypto ++ AES与标准fips不匹配197

1 个答案: