如何使用ASMX Web服务中的WS-Security和Access UsernameToken？

// 服务端代码示例
using System.Web.Services.Protocols;
using System.Security.Cryptography.X509Certificates;

[WebService(Namespace = "http://tempuri.org/")]
[WebServiceBinding(ConformsTo = WsiProfiles.BasicProfile1_1)]
[System.ComponentModel.ToolboxItem(false)]
public class MyWebService : System.Web.Services.WebService
{
    [WebMethod]
    public string MyWebMethod()
    {
        // 验证身份和解密请求
        SoapHeader soapHeader = new SoapHeader();
        soapHeader.AccessUsernameToken = new AccessUsernameToken();
        soapHeader.AccessUsernameToken.Username = "myusername";
        soapHeader.AccessUsernameToken.Password = "mypassword";
        this.Header = soapHeader;

        // 处理请求
        // ...

        // 加密响应
        return "myresponse";
    }
}

// 客户端代码示例
using System.Web.Services.Protocols;
using System.Security.Cryptography.X509Certificates;

MyWebService myWebService = new MyWebService();
SoapHeader soapHeader = new SoapHeader();
soapHeader.AccessUsernameToken = new AccessUsernameToken();
soapHeader.AccessUsernameToken.Username = "myusername";
soapHeader.AccessUsernameToken.Password = "mypassword";
myWebService.Header = soapHeader;
string response = myWebService.MyWebMethod();