13

我有一个自托管 WCF 服务器作为本地系统帐户下的 Windows 服务运行。我正在尝试在 c# 中以编程方式创建一个自签名证书，以便使用消息级安全性与 net.tcp 端点一起使用。

我正在使用以下代码，该代码非常接近如何使用 C# 创建自签名证书？有一些小的改变试图解决我的问题。

public static X509Certificate2 CreateSelfSignedCertificate(string subjectName, TimeSpan expirationLength)
{
    // create DN for subject and issuer
    var dn = new CX500DistinguishedName();
    dn.Encode("CN=" + subjectName, X500NameFlags.XCN_CERT_NAME_STR_NONE);

    CX509PrivateKey privateKey = new CX509PrivateKey();
    privateKey.ProviderName = "Microsoft Strong Cryptographic Provider";
    privateKey.Length = 1024;
    privateKey.KeySpec = X509KeySpec.XCN_AT_KEYEXCHANGE;
    privateKey.KeyUsage = X509PrivateKeyUsageFlags.XCN_NCRYPT_ALLOW_DECRYPT_FLAG | X509PrivateKeyUsageFlags.XCN_NCRYPT_ALLOW_KEY_AGREEMENT_FLAG;
    privateKey.MachineContext = true;
    privateKey.ExportPolicy = X509PrivateKeyExportFlags.XCN_NCRYPT_ALLOW_EXPORT_FLAG;
    privateKey.Create();

    // Use the stronger SHA512 hashing algorithm
    var hashobj = new CObjectId();
    hashobj.InitializeFromAlgorithmName(ObjectIdGroupId.XCN_CRYPT_HASH_ALG_OID_GROUP_ID,
        ObjectIdPublicKeyFlags.XCN_CRYPT_OID_INFO_PUBKEY_ANY,
        AlgorithmFlags.AlgorithmFlagsNone, "SHA1");

    // Create the self signing request
    var cert = new CX509CertificateRequestCertificate();
    cert.InitializeFromPrivateKey(X509CertificateEnrollmentContext.ContextMachine, privateKey, "");
    cert.Subject = dn;
    cert.Issuer = dn; // the issuer and the subject are the same
    cert.NotBefore = DateTime.Now.Date;
    // this cert expires immediately. Change to whatever makes sense for you
    cert.NotAfter = cert.NotBefore + expirationLength;
    //cert.X509Extensions.Add((CX509Extension)eku); // add the EKU
    cert.HashAlgorithm = hashobj; // Specify the hashing algorithm
    cert.Encode(); // encode the certificate

    // Do the final enrollment process
    var enroll = new CX509Enrollment();
    enroll.InitializeFromRequest(cert); // load the certificate
    enroll.CertificateFriendlyName = subjectName; // Optional: add a friendly name
    string csr = enroll.CreateRequest(); // Output the request in base64
    // and install it back as the response
    enroll.InstallResponse(InstallResponseRestrictionFlags.AllowUntrustedCertificate,
        csr, EncodingType.XCN_CRYPT_STRING_BASE64, ""); // no password
    // output a base64 encoded PKCS#12 so we can import it back to the .Net security classes
    var base64encoded = enroll.CreatePFX("", // no password, this is for internal consumption
        PFXExportOptions.PFXExportChainWithRoot);

    // instantiate the target class with the PKCS#12 data (and the empty password)
    return new System.Security.Cryptography.X509Certificates.X509Certificate2(
        System.Convert.FromBase64String(base64encoded), "",
        // mark the private key as exportable (this is usually what you want to do)
        // mark private key to go into the Machine store instead of the current users store
        X509KeyStorageFlags.Exportable | X509KeyStorageFlags.MachineKeySet
    );
}

我用这段代码存储它：

X509Store store = new X509Store(storeName, StoreLocation.LocalMachine);
store.Open(OpenFlags.ReadWrite);
store.Add(newCert);
store.Close();

这将创建证书并将其放入 LocalMachine 证书存储区。问题是当我尝试启动 WCF 服务时，出现以下异常：

证书“CN=myCertificate”可能没有能够进行密钥交换的私钥，或者进程可能没有私钥的访问权限。有关详细信息，请参阅内部异常。内部异常：键集不存在

我的证书的 FindPrivateKey 示例 ( http://msdn.microsoft.com/en-us/library/aa717039%28v=vs.100%29.aspx ) 的输出是：

Private key directory:
C:\ProgramData\Microsoft\Crypto\RSA\MachineKeys
Private key file name:
f0d47c7826b8ef5148b6d412f1c40024_4a8a026f-58e4-40f7-b779-3ae9b6aae1a7

我可以在资源管理器中看到这个 1.43KB 的文件。如果我查看属性|安全性，我会看到 SYSTEM 和 Administrators 都具有完全控制权。

在研究这个错误时，我看到了很多关于私钥丢失或权限不正确的答案。我看不出有什么问题。

真正奇怪的是，如果我使用 mmc 证书插件，请转到证书并选择所有任务|管理私钥...我看到相同的安全设置。查看此内容后，即使我只是打开对话框并点击取消按钮，证书现在在 WCF 中也可以正常工作。我可以简单地重新启动服务，一切都运行良好。

如果我使用 MakeCert 创建证书，它从一开始就可以正常工作。我不知道它有什么不同。

另一条可能不相关的信息是，证书不仅放入了我告诉它放入的 My store 中，而且还放入了“Intermediate Certification Authorities”商店中。我不知道为什么或是否重要。

所以......任何想法我做错了什么？

更新：嗯，这不仅仅是 WCF 问题。当我尝试使用证书通过 http.sys 使用HttpSetServiceConfiguration绑定到端点时，我基本上遇到了同样的问题。该方法返回 1312 -“指定的登录会话不存在。它可能已经被终止”。这实际上不是真正的错误。我在安全事件日志中看到了一个审计失败，上面写着：

Cryptographic Parameters:
    Provider Name:  Microsoft Software Key Storage Provider
    Algorithm Name: Not Available.
    Key Name:   {A23712D0-9A7B-4377-89DB-B1B39E3DA8B5}
    Key Type:   Machine key.

Cryptographic Operation:
    Operation:  Open Key.
    Return Code:    0x80090011

0x80090011 是找不到对象。所以这似乎是同样的问题。同样，在我打开证书的“管理私钥”对话框后，它也可以完美运行。

我仍在寻找问题的原因。

更新＃2：我能够使用下面接受的答案来完成这项工作。有趣的是，此代码现在似乎将证书放入 Machine store 中，而无需调用 X509Store 代码。我仍然调用代码，因为我不确定并且它不会伤害任何东西。这是我用来创建证书的最终代码。

    static public X509Certificate2 CreateSelfSignedCertificate(string subjectName, TimeSpan expirationLength)
    {
        // create DN for subject and issuer
        var dn = new CX500DistinguishedName();
        dn.Encode("CN=" + subjectName, X500NameFlags.XCN_CERT_NAME_STR_NONE);

        CX509PrivateKey privateKey = new CX509PrivateKey();
        privateKey.ProviderName = "Microsoft Strong Cryptographic Provider";
        privateKey.Length = 2048;
        privateKey.KeySpec = X509KeySpec.XCN_AT_KEYEXCHANGE;
        privateKey.KeyUsage = X509PrivateKeyUsageFlags.XCN_NCRYPT_ALLOW_DECRYPT_FLAG | X509PrivateKeyUsageFlags.XCN_NCRYPT_ALLOW_KEY_AGREEMENT_FLAG;
        privateKey.MachineContext = true;
        privateKey.ExportPolicy = X509PrivateKeyExportFlags.XCN_NCRYPT_ALLOW_PLAINTEXT_EXPORT_FLAG;
        privateKey.Create();

        // Use the stronger SHA512 hashing algorithm
        var hashobj = new CObjectId();
        hashobj.InitializeFromAlgorithmName(ObjectIdGroupId.XCN_CRYPT_HASH_ALG_OID_GROUP_ID,
            ObjectIdPublicKeyFlags.XCN_CRYPT_OID_INFO_PUBKEY_ANY,
            AlgorithmFlags.AlgorithmFlagsNone, "SHA512");

        // Create the self signing request
        var cert = new CX509CertificateRequestCertificate();
        cert.InitializeFromPrivateKey(X509CertificateEnrollmentContext.ContextMachine, privateKey, "");
        cert.Subject = dn;
        cert.Issuer = dn; // the issuer and the subject are the same
        cert.NotBefore = DateTime.Now.Date;
        // this cert expires immediately. Change to whatever makes sense for you
        cert.NotAfter = cert.NotBefore + expirationLength;
        cert.HashAlgorithm = hashobj; // Specify the hashing algorithm
        cert.Encode(); // encode the certificate

        // Do the final enrollment process
        var enroll = new CX509Enrollment();
        enroll.InitializeFromRequest(cert); // load the certificate
        enroll.CertificateFriendlyName = subjectName; // Optional: add a friendly name
        string csr = enroll.CreateRequest(); // Output the request in base64
        // and install it back as the response
        enroll.InstallResponse(InstallResponseRestrictionFlags.AllowUntrustedCertificate,
            csr, EncodingType.XCN_CRYPT_STRING_BASE64, ""); // no password
        // output a base64 encoded PKCS#12 so we can import it back to the .Net security classes
        var base64encoded = enroll.CreatePFX("", // no password, this is for internal consumption
            PFXExportOptions.PFXExportChainWithRoot);

        // instantiate the target class with the PKCS#12 data (and the empty password)
        return new System.Security.Cryptography.X509Certificates.X509Certificate2(
            System.Convert.FromBase64String(base64encoded), "",
            // mark the private key as exportable (this is usually what you want to do)
            // mark private key to go into the Machine store instead of the current users store
            X509KeyStorageFlags.Exportable | X509KeyStorageFlags.MachineKeySet | X509KeyStorageFlags.PersistKeySet
        );
    }
4

3 回答 3

5

我在 PowerShell 中使用等效代码时遇到了同样的问题。似乎有时私钥会消失。我使用了进程监视器，您可以看到正在删除的密钥文件。

我解决这个问题的方法是添加X509KeyStorageFlags.PersistKeySet到 X509Certificate2 构造函数中。

于 2013-12-20T16:31:30.467 回答
5

我无法完成这项工作，但我找到了替代解决方案。（2014 年 12 月更新：我现在已经使用接受的答案让它工作了。）

我能够使用PluralSight.Crypto 库来实现我所需要的。我不得不稍微修改源代码以获取存储在 LocalMachine 存储中的私钥。我所做的更改是对文件 CryptContext.cs。我更改了 CreateSelfSignedCertificate 方法。以下是一段代码，包括我所做的更改。本质上，如果 CryptContext 对象在其标志中包含此值，我将 CryptKeyProviderInformation 结构的标志成员设置为 0x20 (CRYPT_MACHINE_KEYSET)。

        byte[] asnName = properties.Name.RawData;
        GCHandle asnNameHandle = GCHandle.Alloc(asnName, GCHandleType.Pinned);

        int flags = 0;                    // New code
        if ((this.Flags & 0x20) == 0x20)  // New code
            flags = 0x20;                 // New code

        var kpi = new Win32Native.CryptKeyProviderInformation
        {
            ContainerName = this.ContainerName,
            KeySpec = (int)KeyType.Exchange,
            ProviderType = 1, // default RSA Full provider
            Flags = flags                 // New code
        };

然后我在自己的代码中使用该函数，如下所示：

        using (Pluralsight.Crypto.CryptContext ctx = new Pluralsight.Crypto.CryptContext()) {

            ctx.Flags = 0x8 | 0x20;
            ctx.Open();

            X509Certificate2 cert = ctx.CreateSelfSignedCertificate(
                new Pluralsight.Crypto.SelfSignedCertProperties
                {
                    IsPrivateKeyExportable = true,
                    KeyBitLength = 4096,
                    Name = new X500DistinguishedName("CN=" + subjectName),
                    ValidFrom = DateTime.Today,
                    ValidTo = DateTime.Today + expirationLength,
                });

            return cert;
        }

请注意，我将 CryptContext 对象的标志设置为 0x8 | 0x20 (CRYPT_NEWKEYSET | CRYPT_MACHINE_KEYSET)。

我希望我能弄清楚我原来的解决方案出了什么问题。但是我需要一些工作，并且在我的测试中，这个解决方案可以满足我的需要。我希望它可以帮助其他人。

于 2013-09-06T16:26:44.873 回答
3

您还可以使用 CodePlex ( https://clrsecurity.codeplex.com/ ) 上的 CLR 安全库。这是创建自签名证书并使用 SSLStream 对其进行测试的示例代码。

        var machineName = Environment.MachineName;
        var keyCreationParameters = new CngKeyCreationParameters();
        keyCreationParameters.KeyUsage = CngKeyUsages.AllUsages;
        keyCreationParameters.KeyCreationOptions = CngKeyCreationOptions.OverwriteExistingKey;
        keyCreationParameters.Parameters.Add(new CngProperty("Length", BitConverter.GetBytes(4096), CngPropertyOptions.None));
        var cngKey = CngKey.Create(CngAlgorithm2.Rsa, "Test", keyCreationParameters);

        var x500DistinguishedName = new X500DistinguishedName("CN=" + machineName);
        x500DistinguishedName.Oid.Value = "1.3.6.1.5.5.7.3.1";
        var certificateCreationParameters = new X509CertificateCreationParameters(x500DistinguishedName);
        certificateCreationParameters.SignatureAlgorithm = X509CertificateSignatureAlgorithm.RsaSha512;
        certificateCreationParameters.TakeOwnershipOfKey = true;
        certificateCreationParameters.CertificateCreationOptions = X509CertificateCreationOptions.None;
        certificateCreationParameters.EndTime = new DateTime(9999, 12,31, 23, 59, 59, 999, DateTimeKind.Utc);
        var certificate = cngKey.CreateSelfSignedCertificate(certificateCreationParameters);

        var certificateStore = new X509Store(StoreName.Root, StoreLocation.CurrentUser);
        certificateStore.Open(OpenFlags.ReadWrite);
        certificateStore.Add(certificate);
        certificateStore.Close();


        var tcpListener = TcpListener.Create(6666);
        tcpListener.Start();
        var client = new TcpClient("localhost", 6666);
        var acceptedClient = tcpListener.AcceptTcpClient();
        var acceptedClinetSslStream = new SslStream(
            acceptedClient.GetStream(), false);
        var serverAuthTask = acceptedClinetSslStream.AuthenticateAsServerAsync(certificate,
                            false, SslProtocols.Tls, true);

        SslStream clientSslStream = new SslStream(
            client.GetStream(),
            false,
            delegate(object o, X509Certificate x509Certificate, X509Chain chain, SslPolicyErrors errors)
                {
                    if (errors == SslPolicyErrors.None)
                        return true;

                    Console.WriteLine("Certificate error: {0}", errors);

                    // Do not allow this client to communicate with unauthenticated servers. 
                    return false;
                },
            null);
        var clientAuthTask = clientSslStream.AuthenticateAsClientAsync(machineName);

        Task.WaitAll(serverAuthTask, clientAuthTask);
于 2015-03-02T21:30:48.170 回答