(Swift) RSA Encrypt Bytes to Base64 and Reverse

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Demonstrates how to RSA encrypt bytes to base64 and the reverse.

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func chilkatTest() {
    // The RSA public key is used for encryption, and the private key for decryption.

    // The public key's role is to make encryption accessible to anyone while ensuring that
    // only the private key holder can decrypt the messages.
    // The public key is designed to be widely distributed so anyone can use it to encrypt messages
    // intended for the owner of the private key.

    // Load our 2048-bit RSA public key.
    let pubKey = CkoPublicKey()!
    // In all Chilkat methods expecting a path, you pass either absolute or relative paths.
    var success: Bool = pubKey.load(fromFile: "qa_data/rsaKeys/myTestRsaPublic.pem")
    if success == false {
        print("\(pubKey.lastErrorText!)")
        return
    }

    let rsa = CkoRsa()!

    // Tell RSA to use the public key.
    rsa.importPublicKeyObj(pubKey)

    // RSA encryption is for small amounts of data, on the order of 200 bytes or less.
    // The maximum number of bytes that can be RSA encrypted depends
    // on the RSA key size and padding scheme (OAEP padding vs PKCS#1 v1.5 padding).
    // For specific limits, see: RSA Encryption Maximum Number of Bytes

    // A typical use for RSA is to encrypt symmetric encryption keys, such as an AES key.
    let prng = CkoPrng()!
    var keyBytes: NSData
    keyBytes = prng.genRandomBytes(32)

    rsa.encodingMode = "base64"
    var encryptedB64: String? = rsa.encryptBytesENC(keyBytes, bUsePrivateKey: false)

    print("Result:")
    print("\(encryptedB64!)")

    // Sample output:
    // hTTV4Lbmm2V7NCw/HaoJL8Aq/MM/HXblQnjitrF9HY1zBlISwui2jGVVZDtZcZ/rICOpPw44w8Qb8AswFVE1sryydmNEvcIfYAp/xgdBPXBERAS0y4AoEzUfuC5TJmJFvnFkl2lX8GAclANfcTik38V+k3EXu5wPzHKNFb07c6jnwh3Jm4f3PRUhmmB2NO5kSWqHsx0dNglOTq5BUZx34nxlXL5G8d7mXqITsUtrOHXAO/Gb7IrvB81Xk2vc5p4yHhiY/rFTHTTmZyzte2qHGm7V6xPRNURjiivnMY2jQU0Um1JKQcAiSe8Suwvd2LXP5PIhl71VLgO+fokjnynfRg==

    // ------------------------------------------------------------------------------------------------------------------------
    // Let's decrypt, which requires the matching private key...

    // Load the matching 2048-bit RSA private key.
    let privKey = CkoPrivateKey()!
    var password: String? = "secret"
    success = privKey.loadAnyFormatFile("qa_data/rsaKeys/myTestRsaPrivate.pem", password: password)
    if success == false {
        print("\(privKey.lastErrorText!)")
        return
    }

    // Tell the RSA object to use the private key.
    rsa.importPrivateKeyObj(privKey)

    var decBytes: NSData
    decBytes = rsa.decryptBytesENC(encryptedB64, bUsePrivateKey: true)
    if success == false {
        print("\(rsa.lastErrorText!)")
        return
    }

    print("Success.")

}