无法使二进制数据上的 RSA signature/verifiction 正常工作。任何工作示例？

Question

我正在尝试对二进制数据使用 RSA 签名和验证，但它不起作用，无论如何 RSA.VerifyData 总是 returns false。

基本上我有一个二进制序列化的对象：

public class MyObject {
    public OtherClass Property1 { get; set; }

    public Trailer Trailer { get; set; }
}

public class Trailer {
    public byte[] Hash {get;set; } // Any hash
    public byte[] Signature {get;set; }
}

基本上对象有自己的属性集，这里只有一个 (Property1)。然后我计算没有预告片的对象的哈希值并将其放在 Trailer.Hash 上。然后我计算 Property1 上的 RSA 签名，Trailer.Hash 和 Trailer.Signature = null。我使用 DataContractSerializer 进行的二进制序列化。

问题是当我检索到哈希值时，它也很好地重新生成（加载时重新计算），但签名验证失败。尝试了很多方法，但似乎没有任何效果。

任何人都可以指出我想做的工作示例吗？我可以签署一个字符串并对其进行验证，但是使用二进制数据我无法让它工作。有关更详细的代码，请参阅我在 Github/

上的 Gist

public void Save(SampleObject model, byte[] cspBlob, string outFilename)
{
    // Calculate the HMACSHA256 over a model with null Trailer section
    CheckTrailer check = new CheckTrailer();    // empty keyed hash and empty signature
    model.Check = null; // both HMAC & Signature are irrelevant for Save because we calculate them here
    check.Trailer1 = model.GetKeyedHash<HMACSHA256>(GetKey());

    DataContractSerializer serializer = new DataContractSerializer(model.GetType());
    using (MemoryStream memoryStream = new MemoryStream())
    {
        model.Check = check;
        // serialize with keyed hash and empty signature
        serializer.WriteObject(memoryStream, model);

        CspParameters cspparams = new CspParameters { Flags = CspProviderFlags.CreateEphemeralKey };
        using (RSACryptoServiceProvider rsaSign = new RSACryptoServiceProvider(cspparams))
        {
            rsaSign.ImportCspBlob(cspBlob);     // must be a key pair blob
            if (rsaSign.PublicOnly)
            {
                throw new CryptographicException("Cannot sign with PUK");
            }

            check.Trailer2 = rsaSign.SignData(memoryStream, HashAlgorithm.Create(DSIG_HASH));
            Console.WriteLine("\tDSIG: {0}", BitConverter.ToString(check.Trailer2));
        }
    }

    // Place the computed signature
    model.Check.Trailer2 = check.Trailer2;

    // serialize
    IFormatter formatter = new BinaryFormatter();
    using (Stream stream = new FileStream(outFilename, FileMode.Create, FileAccess.Write, FileShare.None))
    {
        formatter.Serialize(stream, model);
    }
} // Save()

Answer 1

Can anybody point me to a WORKING example of what I want to do? I can sign a string and verify it but with binary data I cannot get it to work.

RSA 仅在二进制数据上定义，所以问题是您没有生成相同的二进制数据来签名和验证。

根据您的 Save 方法，问题是您签署的是空流，但验证的是非空流。

// New stream.  Position=0, Length=0
using (MemoryStream memoryStream = new MemoryStream())
{
    // Write some data.  After this, Position=X, Length=X
    serializer.WriteObject(memoryStream, model);

    ...

    // RSA.SignData will read from Position until Length in the stream.
    // Since Position=Length already, this means it's the same as calling
    // SignData(Array.Empty<byte>)
    check.Trailer2 = rsaSign.SignData(memoryStream, HashAlgorithm.Create(DSIG_HASH));

在调用 SignData 之前，您需要将内存流的位置重置为 0：

memoryStream.Position = 0;
check.Trailer2 = rsaSign.SignData(memoryStream, ...)

无法使二进制数据上的 RSA signature/verifiction 正常工作。任何工作示例？

Cannot get my RSA signature/verifiction on BINARY data to work. Any working examples?

.net

cryptography

datacontractserializer

signing

binary-serialization