C # RSA PEM decryption characters

1. First step using OpenSSL to convert Pem key to der key//bin>openssl.exe rsa-in rsakeydec.pem-outform der-out pri.der
2, call the following program directly read der converted to C # required XML key, and then ciphertext decryption

usingSystem;usingSystem.IO;usingSystem.Security.Cryptography;usingSystem.Text;namespaceConsoleApplication3 {classProgram {Private Static intgetintegersize (BinaryReader binr) {intcount; varBT =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) {                varHighbyte =Binr.                ReadByte (); varLowbyte =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 dataCount-=1; } binr. Basestream.seek (-1, seekorigin.current);//Last ReadByte wasn ' t a removed zero, so back up a byte            returncount; }        /// <summary>        ///e.g: "d:\\pri.der"; /// </summary>        /// <param name= "FilePath" ></param>        /// <returns></returns>         Public StaticRSACryptoServiceProvider Decodersaprivatekey (stringFilePath) {            byte[] modulus, E, D, P, Q, DP, DQ, IQ; FileStream FS=NewFileStream (Filepath,filemode.open,fileaccess.read); BinaryReader Binr=NewBinaryReader (FS);//Wrap Memory Stream with BinaryReader for easy reading            Try {                varTwobytes =Binr.                ReadUInt16 (); if(Twobytes = =0x8130)//data read as little endian order (actual data order for Sequence)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; varBT =Binr.                ReadByte (); if(BT! =0x00)                    return NULL; varElems =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 =NewRSACryptoServiceProvider (); RSAParameters Rsaparams=NewRSAParameters (); 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); returnRSA; } Catch(Exception e) {Console.WriteLine (E.message+e.stacktrace); return NULL; } finally{Binr.            Close (); }        }        /// <summary>        ///Export private key XML decryption format/// </summary>        /// <returns></returns>         Public Static stringPrivatekeydecxml () {RSACryptoServiceProvider Rsaprovider= Decodersaprivatekey (@"D:\\pri.der"); varPrivatekey = rsaprovider.toxmlstring (true); returnPrivatekey; }        /// <summary>        ///RSA Decryption/// </summary>        /// <param name= "Privatekey" ></param>        /// <param name= "content" ></param>        /// <returns></returns>         Public Static stringRsadecrypt (stringPrivatekey,stringcontent) {RSACryptoServiceProvider RSA=NewRSACryptoServiceProvider (); byte[] cipherbytes; Rsa.            Fromxmlstring (Privatekey); Cipherbytes= RSA. Decrypt (convert.frombase64string (content),false); returnEncoding.UTF8.GetString (cipherbytes); }            Static voidMain (string[] args) {                varStr=Privatekeydecxml (); vars =rsadecrypt (str,"jb6eko9oakc8mymlkorzmj415+s8qf1shr1mipjzcybafhrqdvb+mbz734p45lc2rlejudsy5hrh8i4lvcgsne0kju+ Ge2yy9e8xod3dwutu9/30vv7cebq5wshtjl0myvhtx51x3vrw/oqubh0h3p827gf3c+alplxrvg1ghtc="); }    }}

C # RSA PEM decryption characters