同時(shí)兼容JS和C#的RSA加密解密算法詳解（對(duì)web提交的數(shù)據(jù)加密傳輸）

更新時(shí)間：2017年07月31日 11:52:28 作者：JackWang-CUMT

這篇文章主要給大家介紹了關(guān)于同時(shí)兼容JS和C#的RSA加密解密算法，通過(guò)該算法可以對(duì)web提交的數(shù)據(jù)進(jìn)行加密傳輸，文中通過(guò)圖文及示例代碼介紹的非常詳細(xì)，需要的朋友們可以參考借鑒，下面來(lái)一起看看吧。

前言

我們?cè)赪eb應(yīng)用中往往涉及到敏感的數(shù)據(jù)，由于HTTP協(xié)議以明文的形式與服務(wù)器進(jìn)行交互，因此可以通過(guò)截獲請(qǐng)求的數(shù)據(jù)包進(jìn)行分析來(lái)盜取有用的信息。雖然https可以對(duì)傳輸?shù)臄?shù)據(jù)進(jìn)行加密，但是必須要申請(qǐng)證書(shū)（一般都是收費(fèi)的），成本較高。那么問(wèn)題來(lái)了，如果對(duì)web提交的敏感數(shù)據(jù)進(jìn)行加密呢？web應(yīng)用中，前端的數(shù)據(jù)處理和交互基本上都是靠javascript來(lái)完成，后臺(tái)的邏輯處理可以C#(java)等進(jìn)行處理。

微軟的C#中雖然有RSA算法，但是格式和OpenSSL生成的公鑰/私鑰文件格式并不兼容。這個(gè)也給貫通前后臺(tái)的RSA加密解密帶來(lái)了難度。為了兼容OpenSSL生成的公鑰/私鑰文件格式，貫通javascript和C#的RSA加密解密算法，必須對(duì)C#內(nèi)置的方法進(jìn)行再度封裝。

下面以登錄為例，用戶(hù)在密碼框輸入密碼后，javascript發(fā)送ajax請(qǐng)求時(shí)，對(duì)密碼先進(jìn)行rsa加密后再發(fā)送，服務(wù)器接收到加密后的密碼后，先對(duì)其進(jìn)行解密，然后再驗(yàn)證登錄是否成功。

1、為了進(jìn)行RSA加密解密，首先需要用openssl生成一對(duì)公鑰和私鑰（沒(méi)有的先下載openssl)：

1）打開(kāi)openssl.exe文件，輸入 genrsa -out openssl_rsa_priv.pem 1024

此命令在openssl.exe同目錄下生成openssl_rsa_private_key.pem文件。

2）生成公鑰 rsa -in openssl_rsa__private.pem -pubout -out openssl_rsa__public.pem

以上命令會(huì)創(chuàng)建如下的文件：

這個(gè)文件可以用文本編輯器進(jìn)行打開(kāi)，查看內(nèi)容。

2、用jsencrypt對(duì)密碼進(jìn)行加密：

首先需要導(dǎo)入js包文件

<script src="dist/js/jsencrypt.js"></script>

var encrypt = new JSEncrypt();
var pubkey = "-----BEGIN PUBLIC KEY----- \
 MIGfMA0GCSqGSIb3DQEBAQUAA4GNADCBiQKBgQDAj0dPnBMf3Z4VT1B8Ee6bjKNs \
 hlYj7xvGijAa8RCdmGR7mrtrExnk8mdUlwdcS05gc4SSFOyWJcYtKUHpWn8/pkS0 \
 vgGOl9Bzn0Xt9hiqTb3pZAfykNrMDGZMgJgfD6KTnfzVUAOupvxjcGkcoj6/vV5I \
 eMcx8mT/z3elfsDSjQIDAQAB \
 -----END PUBLIC KEY-----";
encrypt.setPublicKey(pubkey);
var encrypted = encrypt.encrypt($('#txtpwd').val());
//console.log(encrypted);
$.ajax({
 type: "POST",
 url: "http://localhost:24830/services/rsa_pem.ashx",
 data: { "pwd": encrypted },
 dataType: "Json",
 error: function (xhr, status, error) {
  // alert(error);
  $("#txtInfo").text(' 請(qǐng)求服務(wù)器失??！');
  $(that).text('登 錄');
  $(that).attr('disabled', false);
 },
 success: function (json) {
 
 if (uid == "admin" && json.data=="000") {
  window.location.href = "index.html";
 }
 else {
  $("#txtInfo").text(' 用戶(hù)名或者密碼錯(cuò)誤！');
  $(that).text('登 錄');
  $(that).attr('disabled', false);
 }
 }
});

3、后臺(tái)用C#進(jìn)行解密

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

namespace CMCloud.SaaS
{
 public class RSACryptoService
 {
 private RSACryptoServiceProvider _privateKeyRsaProvider;
 private RSACryptoServiceProvider _publicKeyRsaProvider;

 /// <summary>
 /// RSA解密
 /// </summary>
 /// <param name="cipherText"></param>
 /// <returns></returns>
 public string Decrypt(string cipherText)
 {
  if (_privateKeyRsaProvider == null)
  {
  throw new Exception("_privateKeyRsaProvider is null");
  }
  return Decrypt2(cipherText);
 }
 /// <summary>
 /// RSA加密
 /// </summary>
 /// <param name="text"></param>
 /// <returns></returns>
 public string Encrypt(string text)
 {
  if (_publicKeyRsaProvider == null)
  {
  throw new Exception("_publicKeyRsaProvider is null");
  }
  return Encrypt2(text);
  //return Convert.ToBase64String(_publicKeyRsaProvider.Encrypt(Encoding.UTF8.GetBytes(text), false));

 }
 private string Encrypt2(string text)
 {


  Byte[] PlaintextData = Encoding.UTF8.GetBytes(text);
  int MaxBlockSize = _publicKeyRsaProvider.KeySize / 8 - 11;//加密塊最大長(zhǎng)度限制

  if (PlaintextData.Length <= MaxBlockSize)
  {
  return Convert.ToBase64String(_publicKeyRsaProvider.Encrypt(PlaintextData, false));
  }
  else
  {
  using (MemoryStream PlaiStream = new MemoryStream(PlaintextData))
  using (MemoryStream CrypStream = new MemoryStream())
  {
   Byte[] Buffer = new Byte[MaxBlockSize];
   int BlockSize = PlaiStream.Read(Buffer, 0, MaxBlockSize);

   while (BlockSize > 0)
   {
   Byte[] ToEncrypt = new Byte[BlockSize];
   Array.Copy(Buffer, 0, ToEncrypt, 0, BlockSize);

   Byte[] Cryptograph = _publicKeyRsaProvider.Encrypt(ToEncrypt, false);
   CrypStream.Write(Cryptograph, 0, Cryptograph.Length);

   BlockSize = PlaiStream.Read(Buffer, 0, MaxBlockSize);
   }

   return Convert.ToBase64String(CrypStream.ToArray(), Base64FormattingOptions.None);
  }
  }




 }

 private string Decrypt2(string ciphertext)
 {


  Byte[] CiphertextData = Convert.FromBase64String(ciphertext);
  int MaxBlockSize = _privateKeyRsaProvider.KeySize / 8; //解密塊最大長(zhǎng)度限制

  if (CiphertextData.Length <= MaxBlockSize)
  return System.Text.Encoding.UTF8.GetString(_privateKeyRsaProvider.Decrypt(CiphertextData, false));

  using (MemoryStream CrypStream = new MemoryStream(CiphertextData))
  using (MemoryStream PlaiStream = new MemoryStream())
  {
  Byte[] Buffer = new Byte[MaxBlockSize];
  int BlockSize = CrypStream.Read(Buffer, 0, MaxBlockSize);

  while (BlockSize > 0)
  {
   Byte[] ToDecrypt = new Byte[BlockSize];
   Array.Copy(Buffer, 0, ToDecrypt, 0, BlockSize);

   Byte[] Plaintext = _privateKeyRsaProvider.Decrypt(ToDecrypt, false);
   PlaiStream.Write(Plaintext, 0, Plaintext.Length);

   BlockSize = CrypStream.Read(Buffer, 0, MaxBlockSize);
  }

  return System.Text.Encoding.UTF8.GetString(PlaiStream.ToArray());
  }
 }
 public RSACryptoService(string privateKey, string publicKey = null)
 {
  if (!string.IsNullOrEmpty(privateKey))
  {
  _privateKeyRsaProvider = CreateRsaProviderFromPrivateKey(privateKey);
  }

  if (!string.IsNullOrEmpty(publicKey))
  {
  _publicKeyRsaProvider = CreateRsaProviderFromPublicKey(publicKey);
  }
 }

 

 private RSACryptoServiceProvider CreateRsaProviderFromPrivateKey(string privateKey)
 {
  var privateKeyBits = System.Convert.FromBase64String(privateKey);

  var RSA = new RSACryptoServiceProvider();
  var RSAparams = new RSAParameters();

  using (BinaryReader binr = new BinaryReader(new MemoryStream(privateKeyBits)))
  {
  byte bt = 0;
  ushort twobytes = 0;
  twobytes = binr.ReadUInt16();
  if (twobytes == 0x8130)
   binr.ReadByte();
  else if (twobytes == 0x8230)
   binr.ReadInt16();
  else
   throw new Exception("Unexpected value read binr.ReadUInt16()");

  twobytes = binr.ReadUInt16();
  if (twobytes != 0x0102)
   throw new Exception("Unexpected version");

  bt = binr.ReadByte();
  if (bt != 0x00)
   throw new Exception("Unexpected value read binr.ReadByte()");

  RSAparams.Modulus = binr.ReadBytes(GetIntegerSize(binr));
  RSAparams.Exponent = binr.ReadBytes(GetIntegerSize(binr));
  RSAparams.D = binr.ReadBytes(GetIntegerSize(binr));
  RSAparams.P = binr.ReadBytes(GetIntegerSize(binr));
  RSAparams.Q = binr.ReadBytes(GetIntegerSize(binr));
  RSAparams.DP = binr.ReadBytes(GetIntegerSize(binr));
  RSAparams.DQ = binr.ReadBytes(GetIntegerSize(binr));
  RSAparams.InverseQ = binr.ReadBytes(GetIntegerSize(binr));
  }

  RSA.ImportParameters(RSAparams);
  return RSA;
 }

 private int GetIntegerSize(BinaryReader binr)
 {
  byte bt = 0;
  byte lowbyte = 0x00;
  byte highbyte = 0x00;
  int count = 0;
  bt = binr.ReadByte();
  if (bt != 0x02)
  return 0;
  bt = binr.ReadByte();

  if (bt == 0x81)
  count = binr.ReadByte();
  else
  if (bt == 0x82)
  {
  highbyte = binr.ReadByte();
  lowbyte = binr.ReadByte();
  byte[] modint = { lowbyte, highbyte, 0x00, 0x00 };
  count = BitConverter.ToInt32(modint, 0);
  }
  else
  {
  count = bt;
  }

  while (binr.ReadByte() == 0x00)
  {
  count -= 1;
  }
  binr.BaseStream.Seek(-1, SeekOrigin.Current);
  return count;
 }

 private RSACryptoServiceProvider CreateRsaProviderFromPublicKey(string publicKeyString)
 {
  // encoded OID sequence for PKCS #1 rsaEncryption szOID_RSA_RSA = "1.2.840.113549.1.1.1"
  byte[] SeqOID = { 0x30, 0x0D, 0x06, 0x09, 0x2A, 0x86, 0x48, 0x86, 0xF7, 0x0D, 0x01, 0x01, 0x01, 0x05, 0x00 };
  byte[] x509key;
  byte[] seq = new byte[15];
  int x509size;

  x509key = Convert.FromBase64String(publicKeyString);
  x509size = x509key.Length;

  // --------- Set up stream to read the asn.1 encoded SubjectPublicKeyInfo blob ------
  using (MemoryStream mem = new MemoryStream(x509key))
  {
  using (BinaryReader binr = new BinaryReader(mem)) //wrap Memory Stream with BinaryReader for easy reading
  {
   byte bt = 0;
   ushort twobytes = 0;

   twobytes = binr.ReadUInt16();
   if (twobytes == 0x8130) //data read as little endian order (actual data order for Sequence is 30 81)
   binr.ReadByte(); //advance 1 byte
   else if (twobytes == 0x8230)
   binr.ReadInt16(); //advance 2 bytes
   else
   return null;

   seq = binr.ReadBytes(15); //read the Sequence OID
   if (!CompareBytearrays(seq, SeqOID)) //make sure Sequence for OID is correct
   return null;

   twobytes = binr.ReadUInt16();
   if (twobytes == 0x8103) //data read as little endian order (actual data order for Bit String is 03 81)
   binr.ReadByte(); //advance 1 byte
   else if (twobytes == 0x8203)
   binr.ReadInt16(); //advance 2 bytes
   else
   return null;

   bt = binr.ReadByte();
   if (bt != 0x00) //expect null byte next
   return null;

   twobytes = binr.ReadUInt16();
   if (twobytes == 0x8130) //data read as little endian order (actual data order for Sequence is 30 81)
   binr.ReadByte(); //advance 1 byte
   else if (twobytes == 0x8230)
   binr.ReadInt16(); //advance 2 bytes
   else
   return null;

   twobytes = binr.ReadUInt16();
   byte lowbyte = 0x00;
   byte highbyte = 0x00;

   if (twobytes == 0x8102) //data read as little endian order (actual data order for Integer is 02 81)
   lowbyte = binr.ReadByte(); // read next bytes which is bytes in modulus
   else if (twobytes == 0x8202)
   {
   highbyte = binr.ReadByte(); //advance 2 bytes
   lowbyte = binr.ReadByte();
   }
   else
   return null;
   byte[] modint = { lowbyte, highbyte, 0x00, 0x00 }; //reverse byte order since asn.1 key uses big endian order
   int modsize = BitConverter.ToInt32(modint, 0);

   int firstbyte = binr.PeekChar();
   if (firstbyte == 0x00)
   { //if first byte (highest order) of modulus is zero, don't include it
   binr.ReadByte(); //skip this null byte
   modsize -= 1; //reduce modulus buffer size by 1
   }

   byte[] modulus = binr.ReadBytes(modsize); //read the modulus bytes

   if (binr.ReadByte() != 0x02)  //expect an Integer for the exponent data
   return null;
   int expbytes = (int)binr.ReadByte(); // should only need one byte for actual exponent data (for all useful values)
   byte[] exponent = binr.ReadBytes(expbytes);

   // ------- create RSACryptoServiceProvider instance and initialize with public key -----
   RSACryptoServiceProvider RSA = new RSACryptoServiceProvider();
   RSAParameters RSAKeyInfo = new RSAParameters();
   RSAKeyInfo.Modulus = modulus;
   RSAKeyInfo.Exponent = exponent;
   RSA.ImportParameters(RSAKeyInfo);

   return RSA;
  }

  }
 }

 private bool CompareBytearrays(byte[] a, byte[] b)
 {
  if (a.Length != b.Length)
  return false;
  int i = 0;
  foreach (byte c in a)
  {
  if (c != b[i])
   return false;
  i++;
  }
  return true;
 }
 }
}