asp.net 前端JS加密，后端c#解密
近来有一个报名网站原来是内网访问的，近期要放到外网访问，但要求密码不能明文传输。在网上参考了几个帖子并整理出来：
asp.net 前端JS RSA加密，后端c#解密
在分享源码之前，先准备一些东西：
1、下载一个js加密帮助文件，下载地址：https://passport.cnblogs.com/scripts/jsencrypt.min.js，在项目中以JavaScript.js保存，以方便引用：<script type="text/javascript" src="JavaScript.js"></script>，当然了，也可以直接引用网页的，即：<script type="text/javascript" src="https://passport.cnblogs.com/scripts/jsencrypt.min.js"></script>
2、生成一对RSA密钥对，可以在这个网址生成：http://web.chacuo.net/netrsakeypair，也可以下载一个工具来生成。
3、创建一个JsEncryptHelper.cs，包含后台的加密和解决功能，要把第2步生成的密钥对放置在此文件中，之前本来想在前台js中有参调用加密函数来加密不成功，就是我楼上提出的问题。后面就采用JavaScript.js够进行加密了，为了展示效果，把加密的结果保存在文本框中，如果在实际项目中可以把密文保存在一个隐藏的文本框中。后面会把这个类JsEncryptHelper.cs的代码一并分享。
一、前台代码：
<!DOCTYPE html><html xmlns="http://www.w3.org/1999/xhtml"><head runat="server"><meta http-equiv="Content-Type" content="text/html; charset=utf-8"/> <title></title> <script type="text/javascript" src="JavaScript.js"></script> <script language="javascript"> function pwd() { var encrypt = new JSEncrypt(); encrypt.setPublicKey("MIGfMA0GCSqGSIb3DQEBAQUAA4GNADCBiQKBgQCC0hrRIjb3noDWNtbDpANbjt5Iwu2NFeDwU16Ec87ToqeoIm2KI+cOs81JP9aTDk/jkAlU97mN8wZkEMDr5utAZtMVht7GLX33Wx9XjqxUsDfsGkqNL8dXJklWDu9Zh80Ui2Ug+340d5dZtKtd+nv09QZqGjdnSp9PTfFDBY133QIDAQAB"); var str = document.getElementById("tmpPWD").value; var encryptData = encrypt.encrypt(str);//加密后的字符串 console.log(encryptData); document.getElementById("miwen").value = encryptData; }</script></head><body> <form id="form1" runat="server" onsubmit="return pwd();"> <div> 输入密码：<asp:TextBox ID="tmpPWD" runat="server"></asp:TextBox> <br /> 密码加密密文：<asp:TextBox ID="miwen" runat="server" TextMode="MultiLine"></asp:TextBox> <br /> 密文解密：<asp:TextBox ID="mingwen" runat="server"></asp:TextBox> <asp:Button ID="Button1" runat="server" Text="解密" OnClick="Button1_Click" /> </div> </form></body></html>
二、后台解密按钮代码 ：
protected void Button1_Click(object sender, EventArgs e) { JsEncryptHelper newRSA = new JsEncryptHelper(); mingwen.Text = newRSA.Decrypt(miwen.Text); }
三、JsEncryptHelper.cs代码：
using System;using System.Collections.Generic;using System.Linq;using System.Web;using System.IO;using System.Security.Cryptography;using System.Text;using System.Threading.Tasks;/// <summary>/// JsEncryptHelper 的摘要说明/// </summary>/// <summary>/// AJax提交参数加密帮助类/// </summary>public class JsEncryptHelper{ private const string defaultprivateKey = @"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"; private const string defaultpublicKey = @"MIGfMA0GCSqGSIb3DQEBAQUAA4GNADCBiQKBgQCC0hrRIjb3noDWNtbDpANbjt5Iwu2NFeDwU16Ec87ToqeoIm2KI+cOs81JP9aTDk/jkAlU97mN8wZkEMDr5utAZtMVht7GLX33Wx9XjqxUsDfsGkqNL8dXJklWDu9Zh80Ui2Ug+340d5dZtKtd+nv09QZqGjdnSp9PTfFDBY133QIDAQAB"; private RSACryptoServiceProvider _privateKeyRsaProvider; private RSACryptoServiceProvider _publicKeyRsaProvider; public JsEncryptHelper(string privateKey = "", string publicKey = "") { if (string.IsNullOrEmpty(privateKey)) { privateKey = defaultprivateKey; } if (string.IsNullOrEmpty(publicKey)) { publicKey = defaultpublicKey; } if (!string.IsNullOrEmpty(privateKey)) { _privateKeyRsaProvider = CreateRsaProviderFromPrivateKey(privateKey); } if (!string.IsNullOrEmpty(publicKey)) { _publicKeyRsaProvider = CreateRsaProviderFromPublicKey(publicKey); } } public string Decrypt(string cipherText) { if (_privateKeyRsaProvider == null) { throw new Exception("_privateKeyRsaProvider is null"); } if (string.IsNullOrEmpty(cipherText)) { return ""; } return Encoding.UTF8.GetString(_privateKeyRsaProvider.Decrypt(Convert.FromBase64String(cipherText), false)); } public string Encrypt(string text) { if (_publicKeyRsaProvider == null) { throw new Exception("_publicKeyRsaProvider is null"); } return Convert.ToBase64String(_publicKeyRsaProvider.Encrypt(Encoding.UTF8.GetBytes(text), false)); } 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; }}
大概参考了以下几个博客：
https://www.cnblogs.com/alunchen/p/5758585.html
https://www.cnblogs.com/zhangwenbo0713/p/10494945.html
https://blog.csdn.net/k21325/article/details/54409381
感谢以上几个博主，也感谢没有列举出来的参考博客。
如果有哪位朋友参考了本博客后还有疑问的，可以发邮件一并讨论：34341369@qq.com
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