WCF 定制自己的签名验证逻辑

关键点：

1. 保证在客户端设置签名。

client.ClientCredentials.ClientCertificate.SetCertificate(StoreLocation.CurrentUser, StoreName.My, X509FindType.FindBySubjectName, certName);

2. 编写自己的validator，继承 X509CertificateValidator

public class MyX509CertificateValidator : X509CertificateValidator
{
    string allowedIssuerName;

    public MyX509CertificateValidator(string allowedIssuerName)
    {
        if (allowedIssuerName == null)
        {
            throw new ArgumentNullException("allowedIssuerName");
        }

        this.allowedIssuerName = allowedIssuerName;
    }

    public override void Validate(X509Certificate2 certificate)
    {
        // Check that there is a certificate.
        if (certificate == null)
        {
            throw new ArgumentNullException("certificate");
        }

        // Check that the certificate issuer matches the configured issuer.
        if (allowedIssuerName != certificate.IssuerName.Name)
        {
            throw new SecurityTokenValidationException
              ("Certificate was not issued by a trusted issuer");
        }
    }
}

 3. 在server端，将自己编写的validator嵌入servicehost之中

           using (ServiceHost serviceHost = new ServiceHost(typeof(CalculatorService)))
            {
                serviceHost.Credentials.ClientCertificate.Authentication.CertificateValidationMode = 
                    X509CertificateValidationMode.Custom;
                serviceHost.Credentials.ClientCertificate.Authentication.CustomCertificateValidator = 
                    new MyX509CertificateValidator("CN=Contoso.com");

                serviceHost.Open();
                Console.WriteLine("Service started, press ENTER to stop ...");
                Console.ReadLine();

                serviceHost.Close();
            }

最后附上MSDN的官方说明（原文出处）
https://msdn.microsoft.com/en-us/library/ms733806(v=vs.110).aspx