【加密与解密】C#怎么读取pem的KEY文件

1、第一步先用openssl将pem的key转换为der的key //E:\01Doc\bin>openssl.exe rsa -in rsakeydec.pem -outform der -out pri.der
2、调用下面的程序直接读取der转换为c#所需要的xml Key，之后进行密文解密
3、openssl下载地址
http://download.csdn.net/download/jiayanhui2877/4089521

using System;using System.Collections.Generic;using System.Linq;using System.Text;using System.IO;using System.Security.Cryptography;using System.ComponentModel;using System.Runtime.InteropServices;/*refer: http://q.cnblogs.com/q/70822/  http://blog.chinaunix.net/uid-26729093-id-4449165.html*/namespace ConsoleApplication1{    class Program    {        private static int GetIntegerSize(BinaryReader binr)        {            byte bt = 0;            byte lowbyte = 0x00;            byte highbyte = 0x00;            int count = 0;            bt = binr.ReadByte();            if (bt != 0x02)        //expect integer                return 0;            bt = binr.ReadByte();            if (bt == 0x81)                count = binr.ReadByte();    // data size in next byte            else                if (bt == 0x82)                {                    highbyte = binr.ReadByte();    // data size in next 2 bytes                    lowbyte = binr.ReadByte();                    byte[] modint = { lowbyte, highbyte, 0x00, 0x00 };                    count = BitConverter.ToInt32(modint, 0);                }                else                {                    count = bt;        // we already have the data size                }            while (binr.ReadByte() == 0x00)            {    //remove high order zeros in data                count -= 1;            }            binr.BaseStream.Seek(-1, SeekOrigin.Current);        //last ReadByte wasn't a removed zero, so back up a byte            return count;        }        //E:\01Doc\010技术文档\openssl-1.0.2a\OpenSSL_SrcandLib\win32lib\bin>openssl.exe r        //sa -in rsakeydec.txt -outform der -out pri.der        //writing RSA key        public static RSACryptoServiceProvider DecodeRSAPrivateKey(string priKey)        {            //var privkey = Convert.FromBase64String(priKey);            byte[] MODULUS, E, D, P, Q, DP, DQ, IQ;            // ---------  Set up stream to decode the asn.1 encoded RSA private key  ------            //MemoryStream mem = new MemoryStream(privkey);            //BinaryReader binr = new BinaryReader(mem);            string path = @"D:\\project\\ConsoleApplication1\\li_pri.der";              FileStream fs = new FileStream(path, FileMode.Open,FileAccess.Read);              BinaryReader binr = new BinaryReader(fs);    //wrap Memory Stream with BinaryReader for easy reading            byte bt = 0;            ushort twobytes = 0;            int elems = 0;            try            {                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();                if (twobytes != 0x0102) //version number                    return null;                bt = binr.ReadByte();                if (bt != 0x00)                    return null;                //------  all private key components are Integer sequences ----                elems = GetIntegerSize(binr);                MODULUS = binr.ReadBytes(elems);                elems = GetIntegerSize(binr);                E = binr.ReadBytes(elems);                elems = GetIntegerSize(binr);                D = binr.ReadBytes(elems);                elems = GetIntegerSize(binr);                P = binr.ReadBytes(elems);                elems = GetIntegerSize(binr);                Q = binr.ReadBytes(elems);                elems = GetIntegerSize(binr);                DP = binr.ReadBytes(elems);                elems = GetIntegerSize(binr);                DQ = binr.ReadBytes(elems);                elems = GetIntegerSize(binr);                IQ = binr.ReadBytes(elems);                // ------- create RSACryptoServiceProvider instance and initialize with public key -----                RSACryptoServiceProvider RSA = new RSACryptoServiceProvider();                RSAParameters RSAparams = new RSAParameters();                RSAparams.Modulus = MODULUS;                RSAparams.Exponent = E;                RSAparams.D = D;                RSAparams.P = P;                RSAparams.Q = Q;                RSAparams.DP = DP;                RSAparams.DQ = DQ;                RSAparams.InverseQ = IQ;                RSA.ImportParameters(RSAparams);                return RSA;            }            catch (Exception e)            {                Console.WriteLine(e.Message + e.StackTrace);                return null;            }            finally            {                binr.Close();            }        }        /************************************************************************/        /* 你的是pem key，需要下转换为c# rsa provider认识的key。            首先，干掉头部和尾部的无用字符，然后利用如下方法转换：*/        /************************************************************************/        public static void PrivateKeyDecFun()        {            string priKey = @"-----BEGIN RSA PRIVATE KEY-----                MIICWwIBAAKBgQCf1a4LQyipBqeUCZ9kKsfasQzkEFCBmGsM21Sakb5BO0sY07GD                cproJHF2xNQrV0cM7+liE3pBUFsarui2WaHZhAibpLbl9z4FSfoN5hSg6sEgbB17                SvKe3ZN/75GoEsQiQtYW4gUJgzrBovVZ+TeTnN+NHHBqUqBKhNIgPFVapQIDAQAB                AoGAG0OMs5kaF3LuJN9bU+/ENXab908dHG4OXJwRG2ie5muhzLNXhU+IQu7sd9Dt                TBNQKFHIIpWl9fwp/iw1v90cMUQGj0zhSXHAz7Vak/ryQLTyeIIciL8MQWvnbAaN                lIoFq2wBl7SYs3n71B4MlvvTysaG0krsjiPh5LVgnBvzjGECQQDcAwe4XnF7SHWO                nfljrG29soKNiUhYKtDGcV9fvam9u50Ek882wvFmsJP+tk+1CXjMRSNlOi40bxKC                uaBa1JOtAkEAufq9FmZHfBFf3e6n57wLiAj5C1MeyHAtt6qdAF49OZJBGZh1pePn                jDGNezFvy7U5bMp7/updisLCFueS5eKB2QJAF84QIMe/OZqedZ7sI/e9LABLlerb                tAZ17nLH4gEQg6HwHFWt3vv6yKSkbrPlLe5nbpqweLxx0WSPOSvCiPFlRQJAPAfF                NQ+6jz+EdDxukgxOpJBQ4ujnjMc42ooFt3KzzHt66+ocP3m66bOs+VDRxy0t5gHN                2FCJ9Ro8T+xbrDxasQJAARHpcG6tE0F+lmUthtep1U8OrF+AQvqDhBq8MYK+/pF/                LRZkFHkqTsj89OyWDlSH3LeYkOWsr9mAFxsvHZ9BSA==                -----END RSA PRIVATE KEY-----";            priKey = priKey.Replace("-----BEGIN RSA PRIVATE KEY-----", "")                .Replace("-----END RSA PRIVATE KEY-----", "");            RSACryptoServiceProvider rsaProvider = DecodeRSAPrivateKey(priKey);            //RSACryptoServiceProvider rsaProvider = DecodeRSAPrivateKey();            //rsaProvider.FromXmlString();            String PrivateKey = rsaProvider.ToXmlString(true);//将RSA算法的私钥导出到字符串PrivateKey中，参数为true表示导出私钥            Console.WriteLine(PrivateKey);            /************************************************************************/            /* 程序运行结果如下：             * <RSAKeyValue><Modulus>n9WuC0MoqQanlAmfZCrH2rEM5BBQgZhrDNtUmpG+QTtLGNOxg3Ka6CRxds                TUK1dHDO/pYhN6QVBbGq7otlmh2YQIm6S25fc+BUn6DeYUoOrBIGwde0rynt2Tf++RqBLEIkLWFuIFCY                M6waL1Wfk3k5zfjRxwalKgSoTSIDxVWqU=</Modulus><Exponent>AQAB</Exponent><P>3AMHuF5x                e0h1jp35Y6xtvbKCjYlIWCrQxnFfX72pvbudBJPPNsLxZrCT/rZPtQl4zEUjZTouNG8SgrmgWtSTrQ==                </P><Q>ufq9FmZHfBFf3e6n57wLiAj5C1MeyHAtt6qdAF49OZJBGZh1pePnjDGNezFvy7U5bMp7/updi                sLCFueS5eKB2Q==</Q><DP>F84QIMe/OZqedZ7sI/e9LABLlerbtAZ17nLH4gEQg6HwHFWt3vv6yKSkb                rPlLe5nbpqweLxx0WSPOSvCiPFlRQ==</DP><DQ>PAfFNQ+6jz+EdDxukgxOpJBQ4ujnjMc42ooFt3Kz                zHt66+ocP3m66bOs+VDRxy0t5gHN2FCJ9Ro8T+xbrDxasQ==</DQ><InverseQ>ARHpcG6tE0F+lmUth                tep1U8OrF+AQvqDhBq8MYK+/pF/LRZkFHkqTsj89OyWDlSH3LeYkOWsr9mAFxsvHZ9BSA==</Inverse                Q><D>G0OMs5kaF3LuJN9bU+/ENXab908dHG4OXJwRG2ie5muhzLNXhU+IQu7sd9DtTBNQKFHIIpWl9fw                p/iw1v90cMUQGj0zhSXHAz7Vak/ryQLTyeIIciL8MQWvnbAaNlIoFq2wBl7SYs3n71B4MlvvTysaG0kr                sjiPh5LVgnBvzjGE=</D></RSAKeyValue>                  请按任意键继续. . .*/            /************************************************************************/        }        public static void PrivateKeyDecFun1()        {            RSACryptoServiceProvider rsaProvider = DecodeRSAPrivateKey(null);            String PrivateKey = rsaProvider.ToXmlString(true);//将RSA算法的私钥导出到字符串PrivateKey中，参数为true表示导出私钥            Console.WriteLine(PrivateKey);        }        static void Main(string[] args)        {            PrivateKeyDecFun();            PrivateKeyDecFun1();            return;        }    }}