ARC4 Encryption (ARCFOUR)

ARC4 (ARCFOUR) encryption. The Chilkat encryption component supports the ARC4 streaming encryption algorithm.

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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;
}

//  Set the encryption algorithm = "arc4"
crypt.CryptAlgorithm = "arc4";

//  KeyLength may range from 1 byte to 256 bytes.
//  (i.e. 8 bits to 2048 bits)
//  ARC4 key sizes are typically in the range of
//  40 to 128 bits.
//  The KeyLength property is specified in bits:
crypt.KeyLength = 128;

//  Note: The PaddingScheme and CipherMode properties
//  do not apply w/ ARC4.  ARC4 does not encrypt in blocks --
//  it is a streaming encryption algorithm. The number of output bytes
//  is exactly equal to the number of input bytes.

//  EncodingMode specifies the encoding of the output for
//  encryption, and the input for decryption.
//  It may be "hex", "url", "base64", or "quoted-printable".
crypt.EncodingMode = "hex";

//  Note: ARC4 does not utilize initialization vectors.  IV's only
//  apply to block encryption algorithms.

//  The secret key must equal the size of the key.
//  For 128-bit encryption, the binary secret key is 16 bytes.
string keyHex;
keyHex = "000102030405060708090A0B0C0D0E0F101112131415161718191A1B1C1D1E1F";
crypt.SetEncodedKey(keyHex,"hex");

//  Encrypt a string...
//  The output length is exactly equal to the input.  In this
//  example, the input string is 44 chars (ANSI bytes) so the
//  output is 44 bytes -- and when hex encoded results in an
//  88-char string (2 chars per byte for the hex encoding).
string encStr;
encStr = crypt.EncryptStringENC("The quick brown fox jumps over the lazy dog.");
MessageBox.Show(encStr);

//  Now decrypt:
string decStr;
decStr = crypt.DecryptStringENC(encStr);
MessageBox.Show(decStr);