C#-是否可以使用RSA SHA512对哈希进行签名

Question

我使用OpenSSL创建了一个自签名证书，如下所示：

openssl req -x509 -sha512 -new keyrsa:2048 -keyout key2.pem -out cert2.pem -days 100

openssl pkcs12 -export -out pkcs12_cert_test2.pfx -inkey key2.pem -in cert2.pem

我在Windows上安装了pkcs12_cert_test2.pfx，证书签名算法值为sha512RSA

然后，我在C#.NET 4.0中对以下内容进行了编码：

public static bool DSHandler(string operation, string path, string devicePath)
{
bool result = false;
CryptoConfig.AddAlgorithm(typeof(USBSaferAppEFB.RsaPkCs1Sha512SignatureDescription),
"http://www.w3.org/2001/04/xmldsig-more#rsa-sha512");
string password = "xxxx";
bool validSignature = false;
byte[] hashchain = generateHash(path);
string digSignFile = Utils.RegVarValue(DIGSIGNFILE);
string subjectDN = Utils.RegVarValue(SUBJECTDN);
if (operation == "sign")
{
byte[] signature = SignFromContainer(hashchain, subjectDN);
if (signature != null)
{
string signaturestring = Convert.ToBase64String(signature);
File.WriteAllBytes(devicePath + digSignFile, signature);
result = true;
}
else
result = false;
}
}
static byte[] SignFromContainer(byte[] hashchain, string certSubject)
{
try
{
X509Store my = new X509Store(StoreName.My, StoreLocation.CurrentUser);
my.Open(OpenFlags.ReadOnly);
RSACryptoServiceProvider csp = null;
foreach (X509Certificate2 cert in my.Certificates)
{
if (cert.Subject.Contains(certSubject))
{
// We found it.
// Get its associated CSP and private key
csp = (RSACryptoServiceProvider)cert.PrivateKey;
}
}
if (csp == null)
{
return null;
}
byte[] myHash = { 59,4,248,102,77,97,142,201,
210,12,224,93,25,41,100,197,
210,12,224,93};
// Sign the hash
return csp.SignHash(hashchain, CryptoConfig.MapNameToOID("SHA-512"));
}
catch (Exception e)
{
log.Logger("Exception: "+e.Message, "debug");
log.Logger(e.StackTrace, "debug");
return null;
}
}

使用一些文章和答案中的解决方案，我有RsaPkCs1Sha512SignatureDescription类，我试图在其中实现和注册签名描述：

public 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)
{
var sigProcessor = (AsymmetricSignatureDeformatter)CryptoConfig.CreateFromName(DeformatterAlgorithm);
sigProcessor.SetKey(key);
sigProcessor.SetHashAlgorithm("SHA-512");
return sigProcessor;
}
public override AsymmetricSignatureFormatter CreateFormatter(AsymmetricAlgorithm key)
{
var sigProcessor =
(AsymmetricSignatureFormatter)CryptoConfig.CreateFromName(FormatterAlgorithm);
sigProcessor.SetKey(key);
sigProcessor.SetHashAlgorithm("SHA-512");
return sigProcessor;
}
}

我已经验证了hash是64字节长，并且它返回一个CryptographicException: Bad Hash。但如果我使用myHashvar(20字节长)，尽管SignHash中指定的算法是SHA512，但它是有效的，并使用SHA1算法对哈希进行签名。

此外，如果我打印csp.SignatureAlgorithm，其值为http://www.w3.org/2000/09/xmldsig#rsa-sha1.为什么签名算法等于http://www.w3.org/2000/09/xmldsig#rsa-sha1是否已安装证书的详细信息显示sha512RSA为签名算法？这一点会是真正的问题吗？如果是，如何正确创建证书？提前感谢！

Answer 1

此过程在.NET 4.6:中得到了简化

byte[] signature;
using (RSA rsa = cert.GetRSAPrivateKey())
{
signature = rsa.SignHash(hash, HashAlgorithmName.SHA512, RSASignaturePadding.Pkcs1);
}

请注意，.NET 4.6 RSA类型不再需要转换为RSACryptoServiceProvider，如果使用GetRSAPrivateKey()(而不是PrivateKey属性)，则返回的对象可能会处理SHA-512签名生成。GetRSAPrivateKey每次也会返回一个唯一的对象，因此您应该适当地处置它。

Answer 2

好的。不需要实现RsaPkCs1Sha512SignatureDescription类或类似的东西，而是指定正确的CSP以允许CryptoAPI使用SHA256或SHA512："Microsoft Enhanced RSA and AES Cryptographic Provider"，类型24。

我们只需要将CSP类型设置为CspParameter，并导出/导入密钥信息：

byte[] privateKeyBlob;
CspParameters cp = new CspParameters(24);
RSACryptoServiceProvider csp = (RSACryptoServiceProvider)cert.PrivateKey;
privateKeyBlob = csp.ExportCspBlob(true);
csp = new RSACryptoServiceProvider(cp);
csp.ImportCspBlob(privateKeyBlob); 
// Sign the hash
return csp.SignHash(hashchain, CryptoConfig.MapNameToOID("SHA-512"));