C # symmetric encryption (3DES) and asymmetric Encryption (RSA) algorithms

C # Implementation of 3DES encryption/decryption algorithm: (Many ways of implementation, for reference only)

public static bool DecryptFromBase64 (string base64string, String Key,out string decryptstring) {Decrypt            String = "";                try {//encode to bytes byte[] key = Hexstringtobytearray (key);                byte[] cryptstring = convert.frombase64string (base64string);                Set IV and key byte[] Tmpiv = {49, 50, 51, 52, 53, 54, 55, 56};                Byte[] Tmpkey = {0, 1, 2, 3, 4, 5, 6, 7, 0, 1, 2, 3, 4, 5, 6, 7, 0, 1, 2, 3, 4, 5, 6, 7};                for (int II = 0; II < ii++) {Tmpkey[ii] = Key[ii];                } TripleDESCryptoServiceProvider DSP = new TripleDESCryptoServiceProvider (); Dsp.                Mode = System.Security.Cryptography.CipherMode.CBC; Dsp.                Padding = System.Security.Cryptography.PaddingMode.PKCS7; ICryptoTransform tridesencrypt = DSP.                CreateDecryptor (Tmpkey, TMPIV); Using (var ms = new MemoryStream (cryptstring))                        {using (var cs = new CryptoStream (MS, Tridesencrypt, CryptoStreamMode.Read)) {                        var sr = new StreamReader (cs, Encoding.UTF8); 2015/11/11 changes to read the entire content, rather than read the first line, this problem is the algorithm bug decryptstring = Sr. ReadToEnd ();//SR.                    ReadLine (); }} DSP.                Clear ();            return true;            } catch (Exception e) {return false;            }} public static bool Crypt3destobase64 (string cryptstring, String Key, out string decryptstring) {            decryptstring = "";                try {//encode to bytes byte[] key = Hexstringtobytearray (key);                byte[] cryptstring = System.Text.Encoding.UTF8.GetBytes (cryptstring); Set IV and key byte[] Tmpiv = {49, 50, 51, 52, 53, 54, 55, 56};                Byte[] Tmpkey = {0, 1, 2, 3, 4, 5, 6, 7, 0, 1, 2, 3, 4, 5, 6, 7, 0, 1, 2, 3, 4, 5, 6, 7};                for (int II = 0; II < ii++) {Tmpkey[ii] = Key[ii];                } TripleDESCryptoServiceProvider DSP = new TripleDESCryptoServiceProvider (); Dsp.                Mode = System.Security.Cryptography.CipherMode.CBC; Dsp.                Padding = System.Security.Cryptography.PaddingMode.PKCS7; ICryptoTransform tridesencrypt = DSP.                CreateEncryptor (Tmpkey, TMPIV); Byte[] results = tridesencrypt. TransformFinalBlock (cryptstring, 0, cryptstring.                Length);                decryptstring = convert.tobase64string (results); Dsp.                Clear ();            return true;            } catch (Exception e) {return false; }} public static byte[] Hexstringtobytearray (string s) {byte[] bUF = new BYTE[S.LENGTH/2]; for (int i = 0; i < BUF. Length; i++) {Buf[i] = (byte) (Chr2hex (S.substring (i * 2, 1)) * 0x10 + chr2hex (s.substring (i * 2 + 1, 1)            ));        } return BUF;                    } private static Byte Chr2hex (string chr) {switch (CHR) {case "0":                return 0x00;                Case "1": Return 0x01;                Case "2": return 0x02;                Case "3": Return 0x03;                Case "4": Return 0x04;                Case "5": Return 0x05;                Case "6": Return 0x06;                Case "7": Return 0x07;                Case "8": return 0x08;                Case "9": return 0x09;                Case "A": Return 0x0a;          Case "B":          return 0x0b;                Case "C": return 0x0c;                Case "D": return 0x0d;                Case "E": Return 0x0e;            Case "F": return 0x0f;        } return 0x00; }

In the above algorithm, the key is a 48-bit string, the other is not specifically to pay attention to.

RSA encryption algorithm (implemented according to MSDN documentation):

        <summary>////Use RSA Asymmetric encryption algorithm to encrypt text content///</summary>//<param name= "Contentby TES "> Encrypted content byte array </param>//<param name=" PublicKey "> Public key </param>//<param name=" D Ooaeppadding "> Recommended for false</param>//<returns> byte[]</returns> public static after encryption byte[] R                Saencryptcontent (byte[]contentbytes,rsaparameters publickey,bool dooaeppadding) {try {                Byte[] EncryptedData; using (RSACryptoServiceProvider Provider = new RSACryptoServiceProvider ()) {provider.                    ImportParameters (PublicKey); EncryptedData = provider.                Encrypt (Contentbytes, dooaeppadding);            } return EncryptedData;            } catch (Exception e) {return null; }}///<summary>//decryption using RSA Asymmetric encryption algorithm//&LT;/SUmmary>//<param name= "cryptcontentbytes" > byte array after encryption </param>//<param name= "Privatekey" &G t; private key </param>///<param Name= "dooaeppadding" > Recommended for false</param>//<returns> decrypted content Group </returns> public Static byte[] Rsadescryptcontent (byte[]cryptcontentbytes,rsaparameters privatekey,bool DoO                aeppadding) {try {byte[] decryptdata; using (RSACryptoServiceProvider Provider = new RSACryptoServiceProvider ()) {provider.                    ImportParameters (Privatekey); Decryptdata = provider.                Decrypt (Cryptcontentbytes, dooaeppadding);            } return decryptdata;                } catch (Exception e) {Console.WriteLine (e.message);            return null; }        }

Methods for using RSA encryption/decryption algorithms:

 　　　　　　　 
Content is the string to be encrypted
            byte[] contentbytes = byteconverter.getbytes (content);            Byte[] encryptbytes;            Byte[] decryptbytes;            The number of bytes to be encrypted cannot exceed the length value of the key by 8 minus 11 (i.e.: RSACRYPTOSERVICEPROVIDER.KEYSIZE/8-one) int maxblocksize; using (RSACryptoServiceProvider provider=new RSACryptoServiceProvider ()) {maxblocksize = provide                R.KEYSIZE/8-11; RSAParameters PublicKey = provider.                Exportparameters (FALSE);  Less than the maximum block value, directly encrypt if (Contentbytes.length <= maxblocksize) {encryptbytes                = Encryptcontent (Contentbytes, PublicKey, false); } else {//chunked encryption using (MemoryStream plaintstream=new                        MemoryStream (Contentbytes)) using (MemoryStream cryptstream=new MemoryStream ()) {                   byte[] buffer = new Byte[maxblocksize];     int blockSize = plaintstream.read (buffer, 0, maxblocksize);                            while (blocksize>0) {byte[] Encryptblock = new Byte[blocksize];                            Array.copy (buffer, encryptblock, blockSize);                            Byte[]encryptedblock=encryptcontent (Encryptblock,publickey,false);                            Cryptstream.write (encryptedblock, 0, encryptedblock.length);                        BlockSize = plaintstream.read (buffer, 0, maxblocksize);                    } encryptbytes = Cryptstream.toarray ();                }}//encrypted string encryptstring = Byteconverter.getstring (encryptbytes);                Console.WriteLine ("End of Encryption");                Console.ReadLine (); Console.ReadLine ();
The following is the decryption process, the decryption process will also have a length limit, can be decrypted by reference to encryption//string encryptstring = byteconverter.getstring (encryptbytes); RSAParameters Privatekey = provider.                Exportparameters (TRUE);                Decryptbytes = Decryptcontent (Encryptbytes, Privatekey, false);                String decryptstring = Byteconverter.getstring (decryptbytes);            Console.WriteLine (decryptstring); }

　　

C # symmetric encryption (3DES) and asymmetric Encryption (RSA) algorithms