/// 
    /// RSA注册码生成验证帮助类    /// 
    public class RSASignature    {        /// 
        /// 生成密匙        /// 
        /// 私匙        /// 公匙>        public static void GenerateKeys(out string privateKey, out string publicKey)        {            using (RSACryptoServiceProvider rsa = new RSACryptoServiceProvider())            {                privateKey = rsa.ToXmlString(true);                publicKey = rsa.ToXmlString(false);            }        }        /// 
        /// RSA签名        /// 
        /// 明文        /// 私匙        /// 
     
      密文
             public static string CreateSignature(string sSource, string sPrivateKey)        {            using (RSACryptoServiceProvider rsa = new RSACryptoServiceProvider())            {                rsa.FromXmlString(sPrivateKey);                RSAPKCS1SignatureFormatter sf = new RSAPKCS1SignatureFormatter(rsa);                sf.SetHashAlgorithm("SHA256");                byte[] source = System.Text.ASCIIEncoding.ASCII.GetBytes(sSource);                SHA256Managed sha2 = new SHA256Managed();                byte[] result = sha2.ComputeHash(source);                byte[] signature = sf.CreateSignature(result);                return Convert.ToBase64String(signature);            }        }        /// 
        /// RSA签名验证        /// 
        /// 密文        /// 需要比较的明文字符串        /// 公匙        /// 
     
      是否相同
             public static bool VerifySignature(string sEncryptSource, string sCompareString, string sPublicKey)        {            try            {                using (RSACryptoServiceProvider rsa = new RSACryptoServiceProvider())                {                    rsa.FromXmlString(sPublicKey);                    RSAPKCS1SignatureDeformatter df = new RSAPKCS1SignatureDeformatter(rsa);                    df.SetHashAlgorithm("SHA256");                    byte[] signature = Convert.FromBase64String(sEncryptSource);                    SHA256Managed sha2 = new SHA256Managed();                    byte[] compareByte = sha2.ComputeHash(ASCIIEncoding.ASCII.GetBytes(sCompareString));                    return df.VerifySignature(compareByte, signature);                }            }            catch (Exception)            {                return false;            }        }    }

改进：将SHA1改为SHA256，提高安全性

测试

string publicKey = "
     
      
       2DF7PLozXLLJb2vTknucTOK8+ucjYlVFOThnRwqULjeSuA2ZlReaBVXRy8PonVkXXfN2tjosy2ToTwHNX4UQP5kkEbBWYk8knOZPF/96OI2GfjGYnwNUT0CIKHda8B8ztfh1LQanNOCrrByHIuGTORL1WR2hlbaIHRrOIRkeOMc=
      
      
       AQAB
      
     ";        string privateKey = "
     
      
       2DF7PLozXLLJb2vTknucTOK8+ucjYlVFOThnRwqULjeSuA2ZlReaBVXRy8PonVkXXfN2tjosy2ToTwHNX4UQP5kkEbBWYk8knOZPF/96OI2GfjGYnwNUT0CIKHda8B8ztfh1LQanNOCrrByHIuGTORL1WR2hlbaIHRrOIRkeOMc=
      
      
       AQAB
      
      
+WLUzPp7LeMmXaZ3Ebcw6+Ks1HA6XlkpfhLS4DOnViw2O1V/8EXFO77KwFLSwlCzfXo1LN0JuTEsacGdU3f5yw==
      3e1K+J8Ns4UrbhQzgIbyGf8JX+VaETWClJSq9vEXelHGfG9/+5bbGvnF4Wo1c/Kdkuz5IQHfYbuTgMU4LpVNdQ==
      
       bV/6IrhMo/B22CX1HNDyZNIyqK1b/BswxnltASXGY1XapyU1imSfPzfLZpQsmUqZnhOmFLoQ1KcLaoqe/IenBw==
      
      
       J3CndT3XEoNlL3/5kyroVcRkZx18fzhyR3OQWqiIEp3711t9dDngIJApIaFddIi2hkkFEV+i0lyinyztiiHQjQ==
      
      
       Fdk/2JOc/gj7YKsKgMEEVC0+X+WlAMhF+PJVgs188vIQSuXJTRi8Z4A214fvX49s2G81Th7KdYUWCvBAeD153Q==
      
      
       wgJFkY2XIgzfb7nXt5BuByFCbfaWblwPLvZK2BnKOF9urvSlaoIvmbIV/0HjsbCNo6YkVguGv0/imWQIpTuIA6O5S1NX/dbYLp2/rSNl0/xSB5ZjX06VAYbeIsB7YWw87+35K8DrIrlZDMP4Mk6h+pawdgLTtIo/tjTpBhCfB+E=
      
     ";        private void btnCreateRegister_Click(object sender, EventArgs e)        {            if (!string.IsNullOrEmpty(txtComputerInfo.Text))            {                txtRegister.Text = RSASignature.CreateSignature(txtComputerInfo.Text.Trim(), privateKey);            }            else            {                MessageBox.Show("请输入机器码！");                txtComputerInfo.Focus();            }        }        private void button1_Click(object sender, EventArgs e)        {            bool result = RSASignature.VerifySignature(txtRegister.Text, txtComputerInfo.Text.Trim(), publicKey);            MessageBox.Show(result.ToString());        }