(Swift 3,4,5...) Example for both AES-128 and ChaCha20 to Encrypt Binary Data

Demonstrates the use of the new EncryptBd and DecryptBd methods introduced in Chilkat v9.5.0.67 to encrypt/decrypt binary bytes.

Note: This example requires Chilkat v9.5.0.67 or greater.

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

    // Load a small JPG file to be encrypted/decrypted.
    let jpgBytes = CkoBinData()!
    var success: Bool = jpgBytes.loadFile("qa_data/jpg/starfish.jpg")
    if success != true {
        print("Failed to load JPG file.")
        return
    }

    // Show the unencrypted JPG bytes in Base64 format.
    // (The "base64_mime" encoding was added in Chilkat v9.5.0.67.
    // The "base64" encoding emits a single line of base64, whereas
    // "base64_mime" will emit multi-line base64 as it would appear
    // in MIME.)
    print("\(jpgBytes.getEncoded("base64_mime")!)")

    // Sample base64_mime JPG data:

    // 	/9j/4AAQSkZJRgABAgEASABIAAD/7Q18UGhvdG9zaG9wIDMuMAA4QklNA+0AAAAAABAASAAAAAEA
    // 	AQBIAAAAAQABOEJJTQPzAAAAAAAIAAAAAAAAAAE4QklNBAoAAAAAAAEAADhCSU0nEAAAAAAACgAB
    // 	AAAAAAAAAAI4QklNA/UAAAAAAEgAL2ZmAAEAbGZmAAYAAAAAAAEAL2ZmAAEAoZmaAAYAAAAAAAEA
    // 	MgAAAAEAWgAAAAYAAAAAAAEANQAAAAEALQAAAAYAAAAAAAE4QklNBBQAAAAAAAQAAAABOEJJTQQM
    // 	...

    let crypt = CkoCrypt2()!

    // Specify the encryption to be used.
    // First we'll do AES-128 CBC
    crypt.cryptAlgorithm = "aes"
    crypt.cipherMode = "cbc"
    crypt.keyLength = 128

    var ivHex: String? = "000102030405060708090A0B0C0D0E0F"
    crypt.setEncodedIV(ivHex, encoding: "hex")

    var keyHex: String? = "000102030405060708090A0B0C0D0E0F101112131415161718191A1B1C1D1E1F"
    crypt.setEncodedKey(keyHex, encoding: "hex")

    // Do the in-place 128-bit AES CBC encryption.
    // The contents of jpgBytes are replaced with the encrypted bytes.
    success = crypt.encryptBd(jpgBytes)
    if success != true {
        print("\(crypt.lastErrorText!)")
        return
    }

    // Examine the JPG bytes again.  The bytes should be different because they are encrypted:
    print("\(jpgBytes.getEncoded("base64_mime")!)")

    // Sample base64_mime encrypted JPG data:

    // 	sbz0babt1WCkQf5xKMdg/baZAcUBO5GVUUDF2BjVqmd+HrqKN+t6hAcqakL/bdo0q9hYmow0Tp1e
    // 	AQ9V9DOiifQUZqWVkR+kL/c45bq8JGFDvgNl0djPt+yYhV789IB/fPH0upx+/ad++WNOlv1IxGMr
    // 	Y1x1oERU/IsiEzafUJdI4kZ6FQo2IPGMF/Rm1h79I7hP1yYUFxvJyz+PzaySAUH1nLsNHyDVY5VY
    // 	O90aH3steRSYbz8C8UF9wQ3qqEIXQNnnixvoNDnmHyY39VoVBI5F6rnPwYDfAk2t8tmuryFqvwAu
    // 	...

    // Decrypt to restore back to the original:
    success = crypt.decryptBd(jpgBytes)
    if success != true {
        print("\(crypt.lastErrorText!)")
        return
    }

    print("\(jpgBytes.getEncoded("base64_mime")!)")

    // 	/9j/4AAQSkZJRgABAgEASABIAAD/7Q18UGhvdG9zaG9wIDMuMAA4QklNA+0AAAAAABAASAAAAAEA
    // 	AQBIAAAAAQABOEJJTQPzAAAAAAAIAAAAAAAAAAE4QklNBAoAAAAAAAEAADhCSU0nEAAAAAAACgAB
    // 	AAAAAAAAAAI4QklNA/UAAAAAAEgAL2ZmAAEAbGZmAAYAAAAAAAEAL2ZmAAEAoZmaAAYAAAAAAAEA
    // 	MgAAAAEAWgAAAAYAAAAAAAEANQAAAAEALQAAAAYAAAAAAAE4QklNBBQAAAAAAAQAAAABOEJJTQQM
    // 	...

    // ----------------------------------------------------------------------------------
    // To do chacha20 encryption, just change the settings:

    crypt.cryptAlgorithm = "chacha20"
    crypt.keyLength = 256
    // The initial count is the initial block counter for the chacha20 algorithm.
    // It can be any integer, but must be set to the same when decrypting.
    crypt.initialCount = 22

    success = crypt.encryptBd(jpgBytes)
    // jpgBytes now contains chacha20 encrypted bytes.

    success = crypt.decryptBd(jpgBytes)
    // jpgBytes is now restored back to the original unencrypted by bytes.

    // Save the bytes to a file..
    success = jpgBytes.writeFile("qa_output/starfish.jpg")

    print("Success.")

}