using System;
using System.Collections.Generic;
using System.Linq;
using System.Security.Cryptography;
using System.Text;
using System.Threading.Tasks;

namespace AllBase
{
    class RsaBase
    {

        /// <summary>  
        /// RSA签名  
        /// </summary>  
        /// <param name="privateKeyJava">私钥</param>  
        /// <param name="data">待签名的内容</param>  
        /// <returns></returns>  
        public static string RSASignJava(string data, string privateKeyJava, string hashAlgorithm = "MD5", string encoding = "UTF-8")
        {
            RSACryptoServiceProvider rsa = new RSACryptoServiceProvider();
            //rsa.FromXmlString();
            //rsa.FromPrivateKeyJavaString(privateKeyJava);//加载私钥  
                                                         //RSAPKCS1SignatureFormatter RSAFormatter = new RSAPKCS1SignatureFormatter(rsa);  
                                                         ////设置签名的算法为MD5 MD5withRSA 签名  
                                                         //RSAFormatter.SetHashAlgorithm(hashAlgorithm);  


            var dataBytes = Encoding.GetEncoding(encoding).GetBytes(data);
            var HashbyteSignature = rsa.SignData(dataBytes, hashAlgorithm);
            return Convert.ToBase64String(HashbyteSignature);

            //byte[] HashbyteSignature = ConvertToRgbHash(data, encoding);  

            //byte[] dataBytes =Encoding.GetEncoding(encoding).GetBytes(data);  
            //HashbyteSignature = rsa.SignData(dataBytes, hashAlgorithm);  
            //return Convert.ToBase64String(HashbyteSignature);  
            //执行签名   
            //EncryptedSignatureData = RSAFormatter.CreateSignature(HashbyteSignature);  
            //return Convert.ToBase64String(RSAFormatter.CreateSignature(HashbyteSignature));  
            //return result.Replace("=", String.Empty).Replace('+', '-').Replace('/', '_');  
        }
        //RSA加密,随机生成公私钥对并作为出参返回
        static public string RSA_Encrypt(string str_Plain_Text, out string str_Public_Key, out string str_Private_Key)
        {
            str_Public_Key = "";
            str_Private_Key = "";
            UnicodeEncoding ByteConverter = new UnicodeEncoding();
            byte[] DataToEncrypt = ByteConverter.GetBytes(str_Plain_Text);
            try
            {
                RSACryptoServiceProvider RSA = new RSACryptoServiceProvider();
                str_Public_Key = Convert.ToBase64String(RSA.ExportCspBlob(false));
                str_Private_Key = Convert.ToBase64String(RSA.ExportCspBlob(true));

                //OAEP padding is only available on Microsoft Windows XP or later. 
                byte[] bytes_Cypher_Text = RSA.Encrypt(DataToEncrypt, false);
                str_Public_Key = Convert.ToBase64String(RSA.ExportCspBlob(false));
                str_Private_Key = Convert.ToBase64String(RSA.ExportCspBlob(true));
                string str_Cypher_Text = Convert.ToBase64String(bytes_Cypher_Text);
                return str_Cypher_Text;
            }
            catch (CryptographicException e)
            {
                Console.WriteLine(e.Message);
                return null;
            }
        }

        //RSA解密
        static public string RSA_Decrypt(string str_Cypher_Text, string str_Private_Key)
        {
            byte[] DataToDecrypt = Convert.FromBase64String(str_Cypher_Text);
            try
            {
                RSACryptoServiceProvider RSA = new RSACryptoServiceProvider();
                //RSA.ImportParameters(RSAKeyInfo);
                byte[] bytes_Public_Key = Convert.FromBase64String(str_Private_Key);
                RSA.ImportCspBlob(bytes_Public_Key);

                //OAEP padding is only available on Microsoft Windows XP or later. 
                byte[] bytes_Plain_Text = RSA.Decrypt(DataToDecrypt, false);
                UnicodeEncoding ByteConverter = new UnicodeEncoding();
                string str_Plain_Text = ByteConverter.GetString(bytes_Plain_Text);
                return str_Plain_Text;
            }
            catch (CryptographicException e)
            {
                Console.WriteLine(e.ToString());
                return null;
            }
        }
    }
}