以编程方式与证书颁发机构通信

Question

我以编程方式处理证书并与证书颁发机构通信。我一直在 Windows 2008R2 上使用 C# 中的 CertClient 和 CertEnroll COM 对象。

我可以生成请求并从 CA 取回证书。我从这个例子开始： http://blogs.msdn.com/b/alejacma/archive/2008/09/05/how-to-create-a-certificate-request-with-certenroll-and-net-c.aspx

我有两个我无法弄清楚的问题。首先是，我怎样才能访问用于生成证书的私钥？作为 IX509PrivateKey 接口一部分的方法似乎不适用于我的测试环境。我给 CA 的请求与私钥不同，对吗？

第二个问题是我在申请证书时似乎无法提供注册代理证书。该 API 的旧版本使用了一个方法 SetSignerCertificate。我在新 API 中找不到等效项。

Answer 1

我给 CA 的请求与私钥不同，对吗？

您只需将公钥传递给 CA。

在请求证书时，我似乎无法提供注册代理证书。

您需要将 PKCS10 包装在 CMS/CMC 中。看看这里https://www.rfc-editor.org/rfc/rfc5272

Answer 2

在 MSDN 上的 Create Enroll on Behalf of Another User Request 下可以找到使用注册代理证书的示例。证书将安装到您指定的证书存储中，您可以像使用任何其他已安装证书一样使用私钥。

完整示例：

// Add references to CERTENROLL (CertEnroll 1.0 Type Library) 
// and CERTCLILib (CertCli 1.0 Type Library)
using CERTCLILib;
using CERTENROLLLib;
using System;
using System.Collections.Generic;
using System.IO;
using System.Linq;
using System.Runtime.InteropServices;
using System.Security.Cryptography.X509Certificates;
using System.Text;
using System.Threading.Tasks;
using X509KeyUsageFlags = CERTENROLLLib.X509KeyUsageFlags;

namespace TestSubmitEnrollment
{
    class Program
    {
        static void Main(string[] args)
        {
            string requesterName = @"DOMAIN\otherUser";
            string caName = @"CA1.DOMAIN.LOCAL\DOMAIN-CA1-CA";
            string template = "User";
            // signerCertificate's private key must be accessible to this process
            var signerCertificate = FindCertificateByThumbprint("3f817d138f32a9a8df2aa6e43b8aed76eb93a932");

            // create a new private key for the certificate
            CX509PrivateKey privateKey = new CX509PrivateKey();
            // http://blogs.technet.com/b/pki/archive/2009/08/05/how-to-create-a-web-server-ssl-certificate-manually.aspx
            privateKey.ProviderName = "Microsoft Enhanced Cryptographic Provider v1.0";
            privateKey.MachineContext = false;
            privateKey.Length = 2048;
            privateKey.KeySpec = X509KeySpec.XCN_AT_KEYEXCHANGE;
            privateKey.ExportPolicy = X509PrivateKeyExportFlags.XCN_NCRYPT_ALLOW_EXPORT_NONE;
            privateKey.Create();

            // PKCS 10 Request
            // we use v1 to avoid compat issues on w2k8
            IX509CertificateRequestPkcs10 req = (IX509CertificateRequestPkcs10)new CX509CertificateRequestPkcs10();
            req.InitializeFromPrivateKey(X509CertificateEnrollmentContext.ContextUser, privateKey, template);

            // PKCS 7 Wrapper
            var signer = new CSignerCertificate();
            signer.Initialize(false, X509PrivateKeyVerify.VerifyAllowUI, EncodingType.XCN_CRYPT_STRING_BASE64_ANY, 
                Convert.ToBase64String(signerCertificate.GetRawCertData()));

            var wrapper = new CX509CertificateRequestPkcs7();
            wrapper.InitializeFromInnerRequest(req);
            wrapper.RequesterName = requesterName;
            wrapper.SignerCertificate = signer;

            // get CSR
            var enroll = new CX509Enrollment();
            enroll.InitializeFromRequest(wrapper);
            var csr = enroll.CreateRequest();
            //File.WriteAllText("csr.p7b", csr);

            // submit
            const int CR_IN_BASE64 = 1, CR_OUT_BASE64 = 1;
            const int CR_IN_PKCS7 = 0x300;
            ICertRequest2 liveCsr = new CCertRequest();
            var disposition = (RequestDisposition)liveCsr.Submit(CR_IN_BASE64 | CR_IN_PKCS7, csr, null, caName);

            if (disposition == RequestDisposition.CR_DISP_ISSUED)
            {
                string resp = liveCsr.GetCertificate(CR_OUT_BASE64);
                //File.WriteAllText("resp.cer", resp);

                // install the response
                var install = new CX509Enrollment();
                install.Initialize(X509CertificateEnrollmentContext.ContextUser);

                install.InstallResponse(InstallResponseRestrictionFlags.AllowUntrustedRoot,
                    resp, EncodingType.XCN_CRYPT_STRING_BASE64_ANY, null);
            }
            else
            {
                Console.WriteLine("disp: " + disposition.ToString());
            }
            Console.WriteLine("done");
            Console.ReadLine();
        }

        private enum RequestDisposition
        {
            CR_DISP_INCOMPLETE = 0,
            CR_DISP_ERROR = 0x1,
            CR_DISP_DENIED = 0x2,
            CR_DISP_ISSUED = 0x3,
            CR_DISP_ISSUED_OUT_OF_BAND = 0x4,
            CR_DISP_UNDER_SUBMISSION = 0x5,
            CR_DISP_REVOKED = 0x6,
            CCP_DISP_INVALID_SERIALNBR = 0x7,
            CCP_DISP_CONFIG = 0x8,
            CCP_DISP_DB_FAILED = 0x9
        }

        private static X509Certificate2 FindCertificateByThumbprint(string sslCertThumbprint)
        {
            X509Store store = new X509Store(StoreName.My, StoreLocation.CurrentUser);
            try
            {
                store.Open(OpenFlags.ReadOnly);

                var certs = store.Certificates.Find(X509FindType.FindByThumbprint, sslCertThumbprint, true);
                if (certs.Count > 0)
                {
                    return certs[0];
                }
                else
                {
                    throw new KeyNotFoundException();
                }
            }
            finally
            {
                store.Close();
            }
        }

        // we re-declare this to account for backcompat to 2k8
        [ComImport, Guid("884E2042-217D-11DA-B2A4-000E7BBB2B09")]
        class CX509CertificateRequestPkcs10
        {
        }
    }
}