ASP.NET JS使用JSEncrypt 加密，C#使用RSA解密

1.前端加密使用公钥，后端解密使用秘钥，公钥和秘钥可以用网上工具生成。

2.前端源码：

import { JSEncrypt } from 'jsencrypt'
 
// 公钥
const key = `xxxx`
 
// 加密
export function setEncrypt (msg) {
  const jsencrypt = new JSEncrypt()
  jsencrypt.setPublicKey(key)
  return jsencrypt.encrypt(msg)
}

 

 

后端源码：

JsEncryptHelper newRSA = new JsEncryptHelper();
var aaa=newRSA.Decrypt("xxxx");

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;

namespace UnitTest
{
    /// <summary>
    /// AJax提交参数加密帮助类
    /// </summary>
    public class JsEncryptHelper
    {

        private const string defaultprivateKey = @"yyyyy";
        private const string defaultpublicKey = @"xxxx";
        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;

        }
    }
}