Generate Psuedo-Random Data using ARC4 as a PRNG

Download: Chilkat .NET Assemblies

This example demonstrates how to use the ARC4 stream encryption algorithm as a pseudo-random number generator (PRNG). This example generates the random data as hex encoded strings. The EncryptStringENC method can be replaced with EncryptBytes to generate random bytes. Note: This example uses new features available in the pre-release, or any official new version released after 17-October-2007.

Chilkat.Crypt2 crypt = new Chilkat.Crypt2();

bool success;
success = crypt.UnlockComponent("Anything for 30-day trial");
if (success != true) {
    MessageBox.Show("Crypt component unlock failed");
    return;
}

crypt.CryptAlgorithm = "arc4";
crypt.KeyLength = 128;

crypt.SetEncodedKey("000102030405060708090A0B0C0D0E0F","hex");

crypt.EncodingMode = "hex";

//  We will repeatedly feed these 8-bytes of data to
//  the ARC4 stream encryptor to generate our pseudo-random
//  sequence.
string strData;
strData = "012345678";

//  Set FirstChunk to true to initialize the ARC4 PRNG with the key.
crypt.FirstChunk = true;
crypt.LastChunk = false;

string encryptedText;
encryptedText = crypt.EncryptStringENC(strData);
textBox1.Text += encryptedText + "\r\n";
textBox1.Refresh();

//  Set FirstChunk to false to continue encrypting
//  without re-initializing the ARC4 PRNG
crypt.FirstChunk = false;

int i;
for (i = 1; i <= 15; i++) {
    //  Repeatedly encrypting the same 8 bytes of data
    //  produces then pseudo-random sequence.
    encryptedText = crypt.EncryptStringENC(strData);
    textBox1.Text += encryptedText + "\r\n";
    textBox1.Refresh();
}