Csharp/C Sharp/Development Class/ICryptoStream

Decrypting data.

<source lang="csharp">

using System; using System.IO; using System.Security; using System.Security.Cryptography; public class StoreCryptoStream : ICryptoStream {

   static byte[] tag1 = {(byte)"[",(byte)"S",(byte)"a",(byte)"u" ,(byte)"d" ,(byte)"e",(byte)"s" ,(byte)"]"};
   static byte[] tag2 = {(byte)"[",(byte)"S",(byte)"a",(byte)"u" ,(byte)"r" ,(byte)"c",(byte)"2" ,(byte)"]"};
   FileStream fs;
   public StoreCryptoStream(FileStream fout) {
       fs = fout;
   }
   public virtual void CloseStream() { fs.Close(); }
   public virtual void CloseStream(Object obj) { fs.Close(); }
   public virtual void SetSink(ICryptoStream pstm) { }
   public virtual void SetSource(CryptographicObject co) { }
   public virtual ICryptoStream GetSink() { return null; }
   public virtual void Write(byte[] bin) {
       int len = bin.GetLength(0);
       Write(bin, 0, len);
   }
   public virtual void Write(byte[] bin, int start, int len) {
       fs.Write(bin, start, len);
   }

} public class MainClass {

   static byte[] symKey;
   static byte[] symIV;
   private static bool GenerateKey(string password) {
           int len;
           char[] cp = password.ToCharArray();
           len = cp.GetLength(0);
           byte[] bt = new byte[len];
           for (int i = 0; i < len; i++) {
               bt[i] = (byte)cp[i];
           }
           symKey = new byte[8];
           symIV = new byte[8];
           SHA1_CSP sha = new SHA1_CSP();
           sha.Write(bt);
           sha.CloseStream();
           for (int i = 0; i < 8; i++) {
               symKey[i] = sha.Hash[i];
           }
           for (int i = 8; i < 16; i++) {
               symIV[i - 8] = sha.Hash[i];
           }
           return true;
   }
   private static void DecryptData(string infile, string outfile) {
           FileStream fin = new FileStream(infile, FileMode.Open, FileAccess.Read);
           FileStream fout = new FileStream(outfile, FileMode.OpenOrCreate, FileAccess.Write);
           fout.SetLength(0);
           byte[] bin = new byte[4096];
           long totlen = fin.Length;
           long rdlen = 8;
           int len;
           SymmetricAlgorithm des = new DES_CSP();
           StoreCryptoStream scs = new StoreCryptoStream(fout);
           SymmetricStreamDecryptor ssd = des.CreateDecryptor(symKey, symIV);
           ssd.SetSink(scs);
           scs.SetSource(ssd);
           while (rdlen < totlen) {
               len = fin.Read(bin, 0, 4096);
               ssd.Write(bin, 0, len);
               rdlen = rdlen + len;
           }
           ssd.CloseStream();
           fin.Close();
           fout.Close();
   }
   public static void Main(string[] args) {
       GenerateKey(args[0]);
       DecryptData(args[1], args[2]);
   }

}

</source>

Encrypting data.

<source lang="csharp">

using System; using System.IO; using System.Security; using System.Security.Cryptography; public class StoreCryptoStream : ICryptoStream {

   static byte[] tag1 = {(byte)"[",(byte)"S",(byte)"a",(byte)"u" ,
       (byte)"d" ,(byte)"e",(byte)"s" ,(byte)"]"};
   static byte[] tag2 = {(byte)"[",(byte)"S",(byte)"a",(byte)"u" ,
       (byte)"r" ,(byte)"c",(byte)"2" ,(byte)"]"};
   FileStream fs;
   public StoreCryptoStream(FileStream fout) {
       fs = fout;
   }
   public virtual void CloseStream() { fs.Close(); }
   public virtual void CloseStream(Object obj) { fs.Close(); }
   public virtual void SetSink(ICryptoStream pstm) { }
   public virtual void SetSource(CryptographicObject co) { }
   public virtual ICryptoStream GetSink() { return null; }
   public virtual void Write(byte[] bin) {
       int len = bin.GetLength(0);
       Write(bin, 0, len);
   }
   public virtual void Write(byte[] bin, int start, int len) {
       fs.Write(bin, start, len);
   }

} public class MainClass {

   static byte[] symKey;
   static byte[] symIV;
   private static bool GenerateKey(string password) {
       try {
           int len;
           char[] cp = password.ToCharArray();
           len = cp.GetLength(0);
           byte[] bt = new byte[len];
           for (int i = 0; i < len; i++) {
               bt[i] = (byte)cp[i];
           }
           symKey = new byte[8];
           symIV = new byte[8];
           SHA1_CSP sha = new SHA1_CSP();
           sha.Write(bt);
           sha.CloseStream();
           for (int i = 0; i < 8; i++) {
               symKey[i] = sha.Hash[i];
           }
           for (int i = 8; i < 16; i++) {
               symIV[i - 8] = sha.Hash[i];
           }
           return true;
       } catch (Exception e) {
           Console.WriteLine("An Exception Occurred in Generating eys:"
               + e.ToString());
           return false;
       }
   }
   private static void EncryptData(string infile, string outfile) {
       try {
           FileStream fin = new FileStream(infile, FileMode.Open, FileAccess.Read);
           FileStream fout = new FileStream(outfile, FileMode.OpenOrCreate, FileAccess.Write);
           fout.SetLength(0);
           byte[] bin = new byte[4096];
           long totlen = fin.Length;
           long rdlen = 0;
           int len;
           SymmetricAlgorithm des = new DES_CSP();
           StoreCryptoStream scs = new StoreCryptoStream(fout);
           SymmetricStreamEncryptor sse = des.CreateEncryptor(symKey, symIV);
           SHA1_CSP sha = new SHA1_CSP();
           sse.SetSink(sha);
           sha.SetSource(sse);
           sha.SetSink(scs);
           scs.SetSource(sha);
           while (rdlen < totlen) {
               len = fin.Read(bin, 0, 4096);
               sse.Write(bin, 0, len);
               rdlen = rdlen + len;
           }
           sse.CloseStream();
           fin.Close();
           fout.Close();
       } catch (Exception e) {
           Console.WriteLine("An exception occurred while encrypting :"
                + e.ToString());
       }
   }
   public static void Main(string[] args) {
       GenerateKey(args[0]);
       EncryptData(args[1], args[2]);
   }

}

</source>