(Swift 3,4,5...) ARC4 Encryption (ARCFOUR)

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

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func chilkatTest() {
    // This example assumes the Chilkat API to have been previously unlocked.
    // See Global Unlock Sample for sample code.

    let crypt = CkoCrypt2()!

    // 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.
    var keyHex: String? = "000102030405060708090A0B0C0D0E0F101112131415161718191A1B1C1D1E1F"
    crypt.setEncodedKey(keyHex, encoding: "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).
    var encStr: String? = crypt.encryptStringENC("The quick brown fox jumps over the lazy dog.")
    print("\(encStr!)")

    // Now decrypt:
    var decStr: String? = crypt.decryptStringENC(encStr)
    print("\(decStr!)")

}