Question

在MSDN site about SignedXml的帮助下，我可以轻松验证XML DSig是否正确。如果使用签名方法sha1，它可以完美地工作。

但是，当我收到SignatureMethod RSA-SHA512 （http://www.w3.org/2001/04/xmldsig-more#rsa-sha512）时， CheckSignature（）会因CryptograhicException而中断：无法为提供的签名算法创建 SignatureDescription。

似乎CheckSignature（）无法验证RSA-SHA512签名。

有谁知道如何检查这类签名？

从MSDN网站获取的代码是：

public static bool VerifyXml(XmlDocument doc, bool removeSignatureElement = false)
{
    // Check arguments.
    if (doc == null)
        throw new ArgumentException("doc");

    // Create a new SignedXml object and pass it the XML document class.
    SignedXml signedXml = new SignedXml(doc);

    // Find the "Signature" node and create a new XmlNodeList object.
    XmlNodeList nodeList = doc.GetElementsByTagName("Signature", Constants.NamespaceDSig);

    // Throw an exception if no signature was found.
    if (nodeList.Count < 1)
    {
        throw new CryptographicException("Verification failed: No Signature was found in the document.");
    }

    // This example only supports one signature for the entire XML document.  Throw an exception if more than one signature was found.
    if (nodeList.Count > 1)
    {
        throw new CryptographicException("Verification failed: More that one signature was found for the document.");
    }

    // Load the first <signature> node.  
    signedXml.LoadXml((XmlElement)nodeList[0]);

    // Check the signature and return the result.
    bool signedCorrectly = signedXml.CheckSignature(); // throws the Exception!!!

    return signedCorrectly;
}

签名的XML是：

<?xml version="1.0" encoding="UTF-8" standalone="no"?>
<Notification xmlns="http://www.xxxxxxxxxxx.xx/xxxxx">
    <xenc:EncryptedData xmlns:xenc="http://www.w3.org/2001/04/xmlenc#" Type="http://www.w3.org/2001/04/xmlenc#Content"> ... </xenc:EncryptedData>
    <ds:Signature xmlns:ds="http://www.w3.org/2000/09/xmldsig#">
        <ds:SignedInfo>
            <ds:CanonicalizationMethod Algorithm="http://www.w3.org/TR/2001/REC-xml-c14n-20010315"/>
            <ds:SignatureMethod Algorithm="http://www.w3.org/2001/04/xmldsig-more#rsa-sha512"/>
            <ds:Reference URI="">
                <ds:Transforms>
                    <ds:Transform Algorithm="http://www.w3.org/2000/09/xmldsig#enveloped-signature"/>
                    <ds:Transform Algorithm="http://www.w3.org/TR/2001/REC-xml-c14n-20010315#WithComments"/>
                </ds:Transforms>
                <ds:DigestMethod Algorithm="http://www.w3.org/2000/09/xmldsig#sha1"/>
                <ds:DigestValue>WsHcyNL7Jh8HSzR9ArzTqomBkHs=</ds:DigestValue>
            </ds:Reference>
        </ds:SignedInfo>
        <ds:SignatureValue>
pWDatSEbypIUVQR9NFmLkB9kKWjMb6rKWGFFvGqT5tOUILeDhMHUqjCRB9v/g6yYdogC9TRWouhz
...VoZAIBs7EqCbLt7RgpB4GHWc9E3qp65NaCgluw==
        </ds:SignatureValue>
        <ds:KeyInfo>
            <ds:X509Data>
                <ds:X509Certificate>
MIIG+zCCBOOgAwIBAgIHAe2+sRfTfDANBgkqhkiG9w0BAQUFADCBkTELMAkGA1UEBhMCQVQxDTAL
...tvawqBjOfkw1yeDzsDMJHfMuAcpYfrEL
                </ds:X509Certificate>
            </ds:X509Data>
        </ds:KeyInfo>
    </ds:Signature>
</Notification>

Answer 1

您可以验证RSA SHA512签名，但您必须自己实施并注册签名说明。

签名说明：

public sealed class RSAPKCS1SHA512SignatureDescription : SignatureDescription
{
    public RSAPKCS1SHA512SignatureDescription()
    {
        KeyAlgorithm = typeof( RSACryptoServiceProvider ).FullName;
        DigestAlgorithm = typeof( SHA512Managed ).FullName;
        FormatterAlgorithm = typeof( RSAPKCS1SignatureFormatter ).FullName;
        DeformatterAlgorithm = typeof( RSAPKCS1SignatureDeformatter ).FullName;
    }

    public override AsymmetricSignatureDeformatter CreateDeformatter( AsymmetricAlgorithm key )
    {
        if( key == null )
        {
            throw new ArgumentNullException( "key" );
        }

        var deformatter = new RSAPKCS1SignatureDeformatter( key );
        deformatter.SetHashAlgorithm( "SHA512" );
        return deformatter;
    }

    public override AsymmetricSignatureFormatter CreateFormatter( AsymmetricAlgorithm key )
    {
        if( key == null )
        {
            throw new ArgumentNullException( "key" );
        }

        var formatter = new RSAPKCS1SignatureFormatter( key );
        formatter.SetHashAlgorithm( "SHA512" );
        return formatter;
    }
}

在您的代码中，您必须使用CryptoConfig注册此说明：

const string XmlDsigRsaSha512 = "http://www.w3.org/2001/04/xmldsig-more#rsa-sha512";
CryptoConfig.AddAlgorithm( typeof( RSAPKCS1SHA512SignatureDescription ), XmlDsigRsaSha512 );

我在Windows 7 64位上使用.Net 4.0进行了测试。

Answer 2

根据我的研究，SignedXml实施仅支持以下签名方法：

http://www.w3.org/2000/09/xmldsig#hmac-sha1
http://www.w3.org/2001/04/xmldsig-more#hmac-sha256
http://www.w3.org/2001/04/xmldsig-more#hmac-sha384
http://www.w3.org/2001/04/xmldsig-more#hmac-sha512
http://www.w3.org/2001/04/xmldsig-more#hmac-md5
http://www.w3.org/2001/04/xmldsig-more#hmac-ripemd160

这些可用于签名和验证。不幸的是，

http://www.w3.org/2001/04/xmldsig-more#rsa-sha512

不支持用作签名算法。

最终，所有加密方法都会降至CryptoConfig.CreateFromName，其中rsa-sha512返回null。

编辑：我可能刚刚找到了一种方法让它发挥作用。以下代码片段适用于我：

        Dictionary<string, object> ht =
            (Dictionary<string, object>)typeof( CryptoConfig ).InvokeMember( 
            "DefaultNameHT", System.Reflection.BindingFlags.GetProperty | 
            System.Reflection.BindingFlags.Static | 
            System.Reflection.BindingFlags.NonPublic, null, typeof( CryptoConfig ), 
            null );

        var o = ht["http://www.w3.org/2000/09/xmldsig#rsa-sha1"];
        ht["http://www.w3.org/2001/04/xmldsig-more#rsa-sha512"] = o;

在签名/验证之前，应将其称为。

这是基于以下观察：实际的哈希验证来自证书，算法名称仅用作保护。如果您认为配置认为支持RSA-SHA512 （通过指向未使用的相同RSA-SHA1格式化程序），事情就会开始起作用。< / p>
Edit2 ：经过进一步调查，涉及咨询来源

http://www.dotnetframework.org/default.aspx/4@0/4@0/untmp/DEVDIV_TFS/Dev10/Releases/RTMRel/ndp/clr/src/ManagedLibraries/Security/System/Security/Cryptography/Xml/SignedXml@cs/1305376/SignedXml@cs

我认为上述解决方案无效。它的作用只会改变签名文档中的签名名称，但不幸的是，签名仍然是使用RSA-SHA1计算的。

使其工作的唯一方法是将RSA-SHA512实现为KeyedHashAlgoritm，因为签名和验证似乎都支持重载版本：

signedXml.ComputeSignature( KeyedHashAlgorithm hash ); signedXml.CheckSignature( KeyedHashAlgorithm hash );

如何在.NET中验证RSA-SHA512 XML签名？

2 个答案: