Encryption and decryption of strings and Images

Class des
{
/// <Summary>
/// Encryption
/// </Summary>
/// <Param name = "ptoencrypt"> </param>
/// <Param name = "skey"> </param>
/// <Returns> </returns>
Public static string md5encrypt (string ptoencrypt, string skey)
{
Descryptoserviceprovider des = new descryptoserviceprovider ();
Byte [] inputbytearray = encoding. Default. getbytes (ptoencrypt );
Des. Key = asciiencoding. ASCII. getbytes (skey );
Des. IV = asciiencoding. ASCII. getbytes (skey );
Memorystream MS = new memorystream ();
Cryptostream cs = new cryptostream (MS, Des. createencryptor (), cryptostreammode. Write );
CS. Write (inputbytearray, 0, inputbytearray. Length );
CS. flushfinalblock ();
Stringbuilder ret = new stringbuilder ();
Foreach (byte B in ms. toarray ())
{
Ret. appendformat ("{0: X2}", B );
}
Ret. tostring ();
Return ret. tostring ();
}

/// <Summary>
/// Encryption
/// </Summary>
/// <Param name = "ptoencrypt"> </param>
/// <Param name = "skey"> </param>
/// <Returns> </returns>
Public static byte [] md5encrypt (byte [] inputbytearray, string skey)
{
Descryptoserviceprovider des = new descryptoserviceprovider ();
Des. Key = asciiencoding. ASCII. getbytes (skey );
Des. IV = asciiencoding. ASCII. getbytes (skey );
Memorystream MS = new memorystream ();
Cryptostream cs = new cryptostream (MS, Des. createencryptor (), cryptostreammode. Write );
CS. Write (inputbytearray, 0, inputbytearray. Length );
CS. flushfinalblock ();
Return Ms. toarray ();
}

/// <Summary>
/// Decrypt
/// </Summary>
/// <Param name = "ptodecrypt"> </param>
/// <Param name = "skey"> </param>
/// <Returns> </returns>
Public static string md5decrypt (string ptodecrypt, string skey)
{
Descryptoserviceprovider des = new descryptoserviceprovider ();
Byte [] inputbytearray = new byte [ptodecrypt. Length/2];
For (INT x = 0; x <ptodecrypt. Length/2; X ++)
{
Int I = (convert. toint32 (ptodecrypt. substring (x * 2, 2), 16 ));
Inputbytearray [x] = (byte) I;
}

Des. Key = asciiencoding. ASCII. getbytes (skey );
Des. IV = asciiencoding. ASCII. getbytes (skey );
Memorystream MS = new memorystream ();
Cryptostream cs = new cryptostream (MS, Des. createdecryptor (), cryptostreammode. Write );
CS. Write (inputbytearray, 0, inputbytearray. Length );
CS. flushfinalblock ();
Stringbuilder ret = new stringbuilder ();
Return System. Text. encoding. Default. getstring (Ms. toarray ());
}

/// <Summary>
/// Decrypt
/// </Summary>
/// <Param name = "ptodecrypt"> </param>
/// <Param name = "skey"> </param>
/// <Returns> </returns>
Public static byte [] md5decrypt (byte [] inputbytearray, string skey)
{
Descryptoserviceprovider des = new descryptoserviceprovider ();
Des. Key = asciiencoding. ASCII. getbytes (skey );
Des. IV = asciiencoding. ASCII. getbytes (skey );
Memorystream MS = new memorystream ();
Cryptostream cs = new cryptostream (MS, Des. createdecryptor (), cryptostreammode. Write );
CS. Write (inputbytearray, 0, inputbytearray. Length );
CS. flushfinalblock ();
Stringbuilder ret = new stringbuilder ();
Return Ms. toarray ();
}

/// <Summary>
/// Generate the key
/// </Summary>
/// <Returns> </returns>
Public static string generatekey ()
{
Descryptoserviceprovider descrypto = (descryptoserviceprovider) descryptoserviceprovider. Create ();
Return asciiencoding. ASCII. getstring (descrypto. Key );
}
}

Main ()

{

 

/* Image file encryption */
String filename = "xiongmao.jpg ";
// Read files or database image information
Filestream myfilestream = new filestream (filename, filemode. Open );
Binaryreader reader = new binaryreader (myfilestream );
Byte [] image = reader. readbytes (INT) myfilestream. Length );
// Encryption
String key = des. generatekey ();
Byte [] jiami = des. md5encrypt (image, key );
// Decrypt
Byte [] imagedata = des. md5decrypt (jiami, key );
// Display the image
Memorystream mstream = new memorystream ();
Mstream. Write (imagedata, 0, imagedata. Length );
Mstream. Flush ();
Bitmap IMG = new Bitmap (mstream );
Picturebox1.image = IMG;

/* String encryption/Decryption */
String S = des. md5encrypt ("fdsa hello, World Expo", key );
String SSS = des. md5decrypt (S, key );

}

==============================

Or

==============================

 

Class des2
{
/// <Summary>
/// DES encryption method
/// </Summary>
/// <Param name = "strplain"> plaintext </param>
/// <Param name = "strpolicey"> key </param>
/// <Param name = "strdesiv"> vector </param>
/// <Returns> ciphertext </returns>
Public static string desencrypt (string strplain, string strpolicey, string strdesiv)
{
Byte [] bytes0000ey = asciiencoding. ASCII. getbytes (strpolicey. substring (0, 8 ));

Byte [] bytesdesiv = asciiencoding. ASCII. getbytes (strdesiv );
Descryptoserviceprovider desencrypt = new descryptoserviceprovider ();
Memorystream msencrypt = new memorystream ();
Cryptostream csencrypt = new cryptostream (msencrypt, desencrypt. createencryptor (bytescipher ey, bytesdesiv), cryptostreammode. Write );
Streamwriter swencrypt = new streamwriter (csencrypt );

Swencrypt. writeline (strplain );
Swencrypt. Close ();
Csencrypt. Close ();
Byte [] bytescipher = msencrypt. toarray ();
Msencrypt. Close ();
Return convert. tobase64string (bytescipher );
}
/// <Summary>
/// Des Decryption Method
/// </Summary>
/// <Param name = "strcipher"> ciphertext </param>
/// <Param name = "strpolicey"> key </param>
/// <Param name = "strdesiv"> vector </param>
/// <Returns> plaintext </returns>
Public static string desdecrypt (string strcipher, string strpolicey, string strdesiv)
{
Byte [] bytes0000ey = asciiencoding. ASCII. getbytes (strpolicey. substring (0, 8 ));
Byte [] bytesdesiv = asciiencoding. ASCII. getbytes (strdesiv );
Byte [] bytescipher = convert. frombase64string (strcipher );
Descryptoserviceprovider desdecrypt = new descryptoserviceprovider ();
Memorystream msdecrypt = new memorystream (bytescipher );
Cryptostream csdecrypt = new cryptostream (msdecrypt, desdecrypt. createdecryptor (bytescipher ey, bytesdesiv), cryptostreammode. Read );
Streamreader srdecrypt = new streamreader (csdecrypt );
String strplaintext = srdecrypt. Readline ();
Srdecrypt. Close ();
Csdecrypt. Close ();
Msdecrypt. Close ();
Return strplaintext;
}

/// <Summary>
/// DES encryption method
/// </Summary>
/// <Param name = "plain"> plaintext </param>
/// <Param name = "strpolicey"> key </param>
/// <Param name = "strdesiv"> vector </param>
/// <Returns> ciphertext </returns>
Public static byte [] desencrypt (byte [] bytesplain, string strpolicey, string strdesiv)
{
Byte [] bytes0000ey = asciiencoding. ASCII. getbytes (strpolicey. substring (0, 8 ));

Byte [] bytesdesiv = asciiencoding. ASCII. getbytes (strdesiv );
Descryptoserviceprovider desencrypt = new descryptoserviceprovider ();
Memorystream msencrypt = new memorystream ();
Cryptostream csencrypt = new cryptostream (msencrypt, desencrypt. createencryptor (bytescipher ey, bytesdesiv), cryptostreammode. Write );
Csencrypt. Write (bytesplain, 0, bytesplain. Length );
Csencrypt. Close ();
Byte [] bytescipher = msencrypt. toarray ();
Msencrypt. Close ();
Return bytescipher;
}
/// <Summary>
/// Des Decryption Method
/// </Summary>
/// <Param name = "bytescipher"> ciphertext </param>
/// <Param name = "strpolicey"> key </param>
/// <Param name = "strdesiv"> vector </param>
/// <Returns> plaintext </returns>
Public static byte [] desdecrypt (byte [] bytescipher, string strpolicey, string strdesiv)
{
Byte [] bytes0000ey = asciiencoding. ASCII. getbytes (strpolicey. substring (0, 8 ));
Byte [] bytesdesiv = asciiencoding. ASCII. getbytes (strdesiv );
Descryptoserviceprovider desdecrypt = new descryptoserviceprovider ();
Memorystream msdecrypt = new memorystream (bytescipher );
Cryptostream csdecrypt = new cryptostream (msdecrypt, desdecrypt. createdecryptor (bytescipher ey, bytesdesiv), cryptostreammode. Read );
Byte [] fromencrypt = new byte [bytescipher. Length];
Csdecrypt. Read (fromencrypt, 0, fromencrypt. Length );
Csdecrypt. Close ();
Msdecrypt. Close ();
Return fromencrypt;
}

}

 

Main ()

{

 

/* Image file encryption */
String filename = "xiongmao.jpg ";
// Read files or database image information
Filestream myfilestream = new filestream (filename, filemode. Open );
Binaryreader reader = new binaryreader (myfilestream );
Byte [] image = reader. readbytes (INT) myfilestream. Length );
// Encryption
Byte [] jiami = des2.desencrypt (image, "abxiongabxiong", "xiongabxcddabxiongabxiongmaocddmaocdd ");
// Decrypt
Byte [] imagedata = des2.desdecrypt (jiami, "abxiongabxiong", "xiongabxcddabxiongabxiongmaocddmaocdd ");
// Display the image
Memorystream mstream = new memorystream ();
Mstream. Write (imagedata, 0, imagedata. Length );
Mstream. Flush ();
Bitmap IMG = new Bitmap (mstream );
Picturebox1.image = IMG;

/* String encryption/Decryption */
String S = des2.desencrypt ("fdsa hello, World Expo", "abxiongabxiong", "xiongabxcddabxiongabxiongmaocddmaocdd ");
String SSS = des2.desdecrypt (S, "abxiongabxiong", "xiongabxcddabxiongabxiongmaocddmaocdd ");

}