RSACryptoServiceProvider rsa = new RSACryptoServiceProvider();
            privateK = rsa.ToXmlString(true);
            publicK = rsa.ToXmlString(false);

using (RSACryptoServiceProvider rsa = new RSACryptoServiceProvider())
            {
                try
                {
                    rsa.FromXmlString(privateK);
                    // 加密对象 
                    RSAPKCS1SignatureFormatter f = new RSAPKCS1SignatureFormatter(rsa);
                    f.SetHashAlgorithm("SHA1");
                    //hash后的数据只能通过密钥解密(为了保证数据的安全，可以用对称加密加密一下数据)
                    byte[] source = System.Text.ASCIIEncoding.ASCII.GetBytes("shuju");
                    SHA1Managed sha = new SHA1Managed();
                    byte[] result = sha.ComputeHash(source);
                    string s = Convert.ToBase64String(result);
                    byte[] b = f.CreateSignature(result);
                    str = Convert.ToBase64String(b);
                    succes();
                }
                catch (Exception es)
                {
                    fail();
                }
            }

using (RSACryptoServiceProvider rsa = new RSACryptoServiceProvider())
            {
                try
                {
                    rsa.FromXmlString(publicK);
                    RSAPKCS1SignatureDeformatter f = new RSAPKCS1SignatureDeformatter(rsa);
                    f.SetHashAlgorithm("SHA1");
                    byte[] key = Convert.FromBase64String(str);
                    SHA1Managed sha = new SHA1Managed();
                    byte[] name = sha.ComputeHash(ASCIIEncoding.ASCII.GetBytes("shuju"));
                    string s = Convert.ToBase64String(name);
                    if (f.VerifySignature(name, key))
                        succes();
                    else
                        fail();
                }
                catch (Exception ee)
                {
                    fail();
                }
            }