Windows Server 2022中自签名证书出现ERR_SSL_KEY_USAGE_INCOMPATIBLE错误

我通过以下C#代码生成自签名证书：

public static X509Certificate2 CreateSelfSignedCertificate(string friendlyName, string password)
{
    // create DN for subject and issuer
    var dnHostName = new CX500DistinguishedName();
    // DN will be in format CN=machinename, DC=domain, DC=local for machinename.domain.local
    dnHostName.Encode(GetMachineDn());
    var dnSubjectName = dnHostName;

    var dn = new CX500DistinguishedName();
    dn.Encode("CN=" + friendlyName, X500NameFlags.XCN_CERT_NAME_STR_NONE);

    //var privateKey = new CX509PrivateKey();
    var typeName = "X509Enrollment.CX509PrivateKey";
    var type = Type.GetTypeFromProgID(typeName);
    if (type == null)
    {
        throw new Exception(typeName + " is not available on your system: 0x80040154 (REGDB_E_CLASSNOTREG)");
    }

    var privateKey = Activator.CreateInstance(type) as IX509PrivateKey;
    if (privateKey == null)
    {
        throw new Exception("Your certlib does not know an implementation of " + typeName +
                            " (in HKLM:\SOFTWARE\Classes\Interface\)!");
    }
    privateKey.ProviderName = "Microsoft Enhanced RSA and AES Cryptographic Provider";
    privateKey.ProviderType = X509ProviderType.XCN_PROV_RSA_AES;
    // key-bitness
    privateKey.Length = 2048;
    privateKey.KeySpec = X509KeySpec.XCN_AT_KEYEXCHANGE;
    privateKey.MachineContext = true;
    // Don't allow export of private key
    privateKey.ExportPolicy = X509PrivateKeyExportFlags.XCN_NCRYPT_ALLOW_EXPORT_NONE;

    // use is not limited
    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");

    // add extended key usage if you want - look at MSDN for a list of possible OIDs
    var oid = new CObjectId();
    oid.InitializeFromValue("1.3.6.1.5.5.7.3.1"); // SSL server
    var oidlist = new CObjectIds { oid };
    var eku = new CX509ExtensionEnhancedKeyUsage();
    eku.InitializeEncode(oidlist);

    // add all IPs of current machine as dns-names (SAN), so a user connecting to our wcf 
    // service by IP still claim-trusts this server certificate
    var objExtensionAlternativeNames = new CX509ExtensionAlternativeNames();
    {
        var altNames = new CAlternativeNames();
        var dnsHostname = new CAlternativeName();
        dnsHostname.InitializeFromString(AlternativeNameType.XCN_CERT_ALT_NAME_DNS_NAME, Environment.MachineName);
        altNames.Add(dnsHostname);
        foreach (var ipAddress in Dns.GetHostAddresses(Dns.GetHostName()))
        {
            if ((ipAddress.AddressFamily == AddressFamily.InterNetwork ||
                 ipAddress.AddressFamily == AddressFamily.InterNetworkV6) && !IPAddress.IsLoopback(ipAddress))
            {
                var dns = new CAlternativeName();
                dns.InitializeFromString(AlternativeNameType.XCN_CERT_ALT_NAME_DNS_NAME, ipAddress.ToString());
                altNames.Add(dns);
            }
        }
        objExtensionAlternativeNames.InitializeEncode(altNames);
    }

    // Create the self signing request
    //var cert = new CX509CertificateRequestCertificate();
    typeName = "X509Enrollment.CX509CertificateRequestCertificate";
    type = Type.GetTypeFromProgID(typeName);
    if (type == null)
    {
        throw new Exception(typeName + " is not available on your system: 0x80040154 (REGDB_E_CLASSNOTREG)");
    }
    var cert = Activator.CreateInstance(type) as IX509CertificateRequestCertificate;
    if (cert == null)
    {
        throw new Exception("Your certlib does not know an implementation of " + typeName +
                            " (in HKLM:\SOFTWARE\Classes\Interface\)!");
    }
    cert.InitializeFromPrivateKey(X509CertificateEnrollmentContext.ContextMachine, privateKey, "");
    cert.Subject = dn;
    cert.Issuer = dn; // the issuer and the subject are the same
    cert.NotBefore = DateTime.Now.AddDays(-1);
    // this cert expires immediately. Change to whatever makes sense for you
    cert.NotAfter = DateTime.Today.AddYears(200);
    cert.X509Extensions.Add((CX509Extension)eku); // add the EKU
    cert.X509Extensions.Add((CX509Extension)objExtensionAlternativeNames);
    cert.HashAlgorithm = hashobj; // Specify the hashing algorithm
    cert.Encode(); // encode the certificate

    // Do the final enrollment process
    //var enroll = new CX509Enrollment();
    typeName = "X509Enrollment.CX509Enrollment";
    type = Type.GetTypeFromProgID(typeName);
    if (type == null)
    {
        throw new Exception(typeName + " is not available on your system: 0x80040154 (REGDB_E_CLASSNOTREG)");
    }
    var enroll = Activator.CreateInstance(type) as IX509Enrollment;
    if (enroll == null)
    {
        throw new Exception("Your certlib does not know an implementation of " + typeName +
                            " (in HKLM:\SOFTWARE\Classes\Interface\)!");
    }
    // Use private key to initialize the certrequest...
    enroll.InitializeFromRequest(cert);
    enroll.CertificateFriendlyName = friendlyName; // Optional: add a friendly name
    var 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, password);

    // This will fail on Win2k8, some strange "Parameter is empty" error... Thus we search the
    // certificate by serial number with the managed X509Store-class
    // // output a base64 encoded PKCS#12 so we can import it back to the .Net security classes
    //var base64Encoded = enroll.CreatePFX(password, PFXExportOptions.PFXExportChainNoRoot, EncodingType.XCN_CRYPT_STRING_BASE64);
    //return new X509Certificate2(Convert.FromBase64String(base64Encoded), password, X509KeyStorageFlags.MachineKeySet | X509KeyStorageFlags.PersistKeySet);
    //CertificateExists(friendlyName);
    var certFs = LoadCertFromStore(friendlyName);
    if (!certFs.HasPrivateKey)
        throw new InvalidOperationException("Created certificate has no private key!");

    return certFs;
}

该代码此前运行正常，但在Windows Server 2022服务器上，使用Chromium内核浏览器（Edge、Opera、Chrome）访问时出现ERR_SSL_KEY_USAGE_INCOMPATIBLE错误，Firefox浏览器则无此问题。

若通过PowerShell命令手动生成自签名证书：

New-SelfSignedCertificate -Subject "CN=WebServer 444" -CertStoreLocation "cert:\LocalMachine\My"

再通过cmd命令绑定SSL证书：

netsh http add sslcert ipport=0.0.0.0:444 appid={"blabla-bla-bla-bla-blabla"} certhash=<THUMBPRINT>

此时证书可正常工作。

环境详情：.NET Framework 4.6.2、Visual Studio 2022

问题原因及解决方法 #

原因分析 #

• 核心问题在于证书的**密钥用法(Key Usage)**字段缺失。你的C#代码仅配置了增强型密钥用法(EKU)（标识为SSL服务器的1.3.6.1.5.5.7.3.1），但没有显式设置密钥用法。
• Windows Server 2022上的Chromium内核浏览器对证书合规性校验更严格，要求服务器证书必须包含数字签名(Digital Signature)和密钥交换(Key Encipherment)这两个密钥用法标识，否则会触发ERR_SSL_KEY_USAGE_INCOMPATIBLE错误。
• PowerShell的New-SelfSignedCertificate命令默认会自动添加符合服务器证书要求的密钥用法，因此手动生成的证书可以正常工作。

解决步骤 #

在C#代码中添加密钥用法扩展，具体操作如下：

1. 创建CX509ExtensionKeyUsage实例并设置所需的密钥用法标志：

// 添加密钥用法扩展
var keyUsage = new CX509ExtensionKeyUsage();
// 启用数字签名和密钥交换，满足SSL服务器证书要求
keyUsage.InitializeEncode(X509KeyUsageFlags.XCN_CERT_DIGITAL_SIGNATURE_KEY_USAGE | X509KeyUsageFlags.XCN_CERT_KEY_ENCIPHERMENT_KEY_USAGE);

2. 将该扩展添加到证书请求的扩展集合中，插入到添加EKU扩展的代码之后：

cert.X509Extensions.Add((CX509Extension)eku); // 原有EKU扩展
cert.X509Extensions.Add((CX509Extension)keyUsage); // 新增密钥用法扩展
cert.X509Extensions.Add((CX509Extension)objExtensionAlternativeNames); // 原有SAN扩展

修改后的代码生成的证书会包含合规的密钥用法，即可在Chromium内核浏览器中正常使用。

内容的提问来源于stack exchange，提问作者Sahin