c# - SSO SAML 的 Signed XML 签名验证(使用 sha256)

Question

在 Windows 2003 服务器上使用 VS 2008 和 .Net Framework 3.5。

为了安全起见，我们已经使用 SAML 实现了 SSO。我们在服务提供商端工作，验证从客户端系统生成的签名 XML SAML Assertuib token 。到目前为止，我们遇到的任何签名文档都使用签名算法“rsa-sha1”，但现在我们有新客户发送了一个使用签名算法“rsa-sha256”的文件，这就是问题所在。

public static string VerifySignature()
{
    if (m_xmlDoc == null)
        return "Could not load XMLDocument ";

    try
    {
        XmlNamespaceManager nsm = new XmlNamespaceManager(new NameTable());
        nsm.AddNamespace("dsig", SignedXml.XmlDsigNamespaceUrl);
        XmlElement sigElt = (XmlElement)m_xmlDoc.SelectSingleNode(
            "//dsig:Signature", nsm);

        // Load the signature for verification
        SignedXml sig = new SignedXml(m_xmlDoc);
        sig.LoadXml(sigElt);

        if (!sig.CheckSignature())
            return "Invalid Signature";
    }
    catch (Exception ex)
    {
        return ex.Message;
    }
    return string.Empty;
}

现在，当我为这个新客户尝试相同的代码(使用签名算法 rsa-sha256h)时 - 这不起作用并且我收到错误“无法为提供的签名算法创建 SignatureDescription。”

最近2-3天看了很多博客和文章，我才知道SignedXml不支持sha256。美好的。但是接下来呢。它在某处提到使用 WIF，我也检查并尝试过 this .

我也在尝试使用 RSAPKCS1SignatureDeformatter 的 VerifySignature 方法。但不太确定要传递的两个参数是什么。

Answer 1

Dotnet 4.6.2+ 内置了较新的 sha 哈希。对于 dotnet 4+，要访问 rsa-sha512、rsa-sha384 和 rsa-sha256，您应该包含此代码某处。

/// <summary>Declare the signature type for rsa-sha512</summary>
public class RsaPkCs1Sha512SignatureDescription : SignatureDescription
{
    public RsaPkCs1Sha512SignatureDescription()
    {
        KeyAlgorithm = typeof(RSACryptoServiceProvider).FullName;
        DigestAlgorithm = typeof(SHA512CryptoServiceProvider).FullName;
        FormatterAlgorithm = typeof(RSAPKCS1SignatureFormatter).FullName;
        DeformatterAlgorithm = typeof(RSAPKCS1SignatureDeformatter).FullName;
    }

    public override AsymmetricSignatureDeformatter CreateDeformatter(AsymmetricAlgorithm key)
    {
        var sigProcessor = (AsymmetricSignatureDeformatter)CryptoConfig.CreateFromName(DeformatterAlgorithm);
        sigProcessor.SetKey(key);
        sigProcessor.SetHashAlgorithm("SHA512");
        return sigProcessor;
    }

    public override AsymmetricSignatureFormatter CreateFormatter(AsymmetricAlgorithm key)
    {
        var sigProcessor =
            (AsymmetricSignatureFormatter)CryptoConfig.CreateFromName(FormatterAlgorithm);
        sigProcessor.SetKey(key);
        sigProcessor.SetHashAlgorithm("SHA512");
        return sigProcessor;
    }
}

/// <summary>Declare the signature type for rsa-sha384</summary>
public class RsaPkCs1Sha384SignatureDescription : SignatureDescription {
    public RsaPkCs1Sha384SignatureDescription()
    {
        KeyAlgorithm = typeof(RSACryptoServiceProvider).FullName;
        DigestAlgorithm = typeof(SHA384CryptoServiceProvider).FullName;
        FormatterAlgorithm = typeof(RSAPKCS1SignatureFormatter).FullName;
        DeformatterAlgorithm = typeof(RSAPKCS1SignatureDeformatter).FullName;
    }

    public override AsymmetricSignatureDeformatter CreateDeformatter(AsymmetricAlgorithm key)
    {
        var sigProcessor = (AsymmetricSignatureDeformatter) CryptoConfig.CreateFromName(DeformatterAlgorithm);
        sigProcessor.SetKey(key);
        sigProcessor.SetHashAlgorithm("SHA384");
        return sigProcessor;
    }

    public override AsymmetricSignatureFormatter CreateFormatter(AsymmetricAlgorithm key)
    {
        var sigProcessor =
            (AsymmetricSignatureFormatter)CryptoConfig.CreateFromName(FormatterAlgorithm);
        sigProcessor.SetKey(key);
        sigProcessor.SetHashAlgorithm("SHA384");
        return sigProcessor;
    }
}

/// <summary>Declare the signature type for rsa-sha256</summary>
public class RsaPkCs1Sha256SignatureDescription : SignatureDescription
{
    public RsaPkCs1Sha256SignatureDescription()
    {
        KeyAlgorithm = typeof(RSACryptoServiceProvider).FullName;
        DigestAlgorithm = typeof(SHA256CryptoServiceProvider).FullName;
        FormatterAlgorithm = typeof(RSAPKCS1SignatureFormatter).FullName;
        DeformatterAlgorithm = typeof(RSAPKCS1SignatureDeformatter).FullName;
    }

    public override AsymmetricSignatureDeformatter CreateDeformatter(AsymmetricAlgorithm key)
    {
        var sigProcessor =
            (AsymmetricSignatureDeformatter) CryptoConfig.CreateFromName(DeformatterAlgorithm);
        sigProcessor.SetKey(key);
        sigProcessor.SetHashAlgorithm("SHA256");
        return sigProcessor;
    }

    public override AsymmetricSignatureFormatter CreateFormatter(AsymmetricAlgorithm key)
    {
        var sigProcessor =
            (AsymmetricSignatureFormatter)CryptoConfig.CreateFromName(FormatterAlgorithm);
        sigProcessor.SetKey(key);
        sigProcessor.SetHashAlgorithm("SHA256");
        return sigProcessor;
    }
}

然后，您应该通过调用这样的代码来激活这些 sig 描述。您只需调用一次，因此您可以根据需要从静态构造函数中调用它。

    CryptoConfig.AddAlgorithm(typeof(RsaPkCs1Sha512SignatureDescription),
        "http://www.w3.org/2001/04/xmldsig-more#rsa-sha512");
    CryptoConfig.AddAlgorithm(typeof(RsaPkCs1Sha384SignatureDescription),
        "http://www.w3.org/2001/04/xmldsig-more#rsa-sha384");
    CryptoConfig.AddAlgorithm(typeof(RsaPkCs1Sha256SignatureDescription),
        "http://www.w3.org/2001/04/xmldsig-more#rsa-sha256");

向Microsoft's Carlos Lopez 致敬和 BitSchupster和 Andrew在 SO 上。