Simple use of. Net Encryption

Symmetric encryption algorithm:

Using system;
Using system. Security. cryptography;
Using system. text;
Using system. IO;

/// <Summary>
/// Example of using symmetric encryption
/// </Summary>
Class class1
{

Static void main (string [] ARGs)
{
Class1 c = new class1 ();
C. startdemo ();
}

Public void startdemo ()
{
// Establish datagric Algorithm
Repeated ricalgorithm SA = Rijndael. Create ();

// Key and IV
SA. generatekey (); // generate a random (32*8) Key.
// SA. generateiv (); // initial vector. You do not need to use IV in ECB mode.
SA. mode = ciphermode. ECB; // block processing mode
SA. Padding = paddingmode. Zeros; // fill mode of the end data block


Console. writeline ("Key is :");
For (INT I = 0; I <SA. Key. length; I ++)
{
Console. Write ("{0: X2}", SA. Key [I]);
}
Console. writeline ("\ n ");


// Establish crypto stream
Memorystream MS = new memorystream ();
Cryptostream cs = new cryptostream (MS, SA. createencryptor (), cryptostreammode. Write );

String plaintext; // the original text.
Byte [] cipherbytes; // encrypted data
Byte [] finalbytes; // decrypted data

Plaintext = "how are you? This is a line of text. ";
Byte [] plainbytes = encoding. utf8.getbytes (plaintext );


Console. writeline ("raw text: \ n {0} \ n", plaintext );
// Display plaint text byte array in hex format
Console. writeline ("raw data is :");
For (INT I = 0; I <plainbytes. length; I ++)
{
Console. Write ("{0: X2}", plainbytes [I]);
}
Console. writeline ("\ n ");

// Encryption process
CS. Write (plainbytes, 0, plainbytes. Length );
CS. Close ();
Cipherbytes = Ms. toarray ();
Ms. Close ();

// Display ciphertext byte array in hex format
Console. writeline ("the encrypted data is :");
For (INT I = 0; I <cipherbytes. length; I ++)
{
Console. Write ("{0: X2}", cipherbytes [I]);
}
Console. writeline ("\ n ");


// The following is the encryption process
MS = new memorystream (cipherbytes );
Cs = new cryptostream (MS, SA. createdecryptor (), cryptostreammode. Read );
Finalbytes = new byte [plainbytes. Length];
CS. Read (finalbytes, 0, plainbytes. Length );

Console. writeline ("the decrypted data is :");
For (INT I = 0; I <finalbytes. length; I ++)
{
Console. Write ("{0: X2}", finalbytes [I]);
}
Console. writeline ("\ n ");

String finaltext = encoding. utf8.getstring (finalbytes );

Console. writeline ("decrypted text: \ n {0} \ n", finaltext );
Console. writeline ("press any key to continue ");
Console. Readline ();


}
}

Asymmetric encryption algorithm:

Using system;
Using system. IO;
Using system. text;
Using system. Security. cryptography;

/** // <Summary>
/// A simple example of using the. NET asymmetric encryption algorithm
/// The program in this example is very simple. It is only used to explain how to use the asymmetric (RSA) algorithm in. net.
/// Kwanhong 2005.9
/// </Summary>
Class class1
{
Public static void main (string [] ARGs)
{
Class1 c = new class1 ();
C. startdemo ();
}

Public void startdemo ()
{
// RSA encryption and decryption process:
// There are two RSA objects: rsa1 and rsa2.
// If you want rsa2 to send a piece of information to rsa1, rsa1 first sends the "Public Key" to rsa2
// The Public Key obtained by rsa2 is used to encrypt the data to be sent.
// After obtaining the encrypted content, rsa1 decrypts it with its own private key to obtain the original data content.

Rsacryptoserviceprovider rsa1 = new rsacryptoserviceprovider ();
Rsacryptoserviceprovider rsa2 = new rsacryptoserviceprovider ();

String publickey;
Publickey = rsa1.toxmlstring (false); // export the public key of rsa1

String plaintext;
Plaintext = "how are you? This is the string used for testing. "; // Raw data
Console. writeline ("raw data is \ n {0} \ n", plaintext );

Rsa2.fromxmlstring (publickey); // rsa2 imports the public key of rsa1 for information encryption.

// Start rsa2 Encryption
Byte [] cipherbytes;
Cipherbytes = rsa2.encrypt (
Encoding. utf8.getbytes (plaintext ),
False );

/**//*////////////////////////////////// ////////////*/
Console. writeline ("the encrypted data is :");
For (INT I = 0; I <cipherbytes. length; I ++)
{
Console. Write ("{0: X2}", cipherbytes [I]);
}
Console. writeline ("\ n ");
/**//*////////////////////////////////// ////////////*/

// Start decryption with rsa1
Byte [] plaintbytes;
Plaintbytes = rsa1.decrypt (cipherbytes, false );

Console. writeline ("the decrypted data is :");
Console. writeline (encoding. utf8.getstring (plaintbytes ));

Console. Readline ();
}

}