Swift

RSA Encrypt/Decrypt Bytes

See more RSA Examples

Demonstrates how to RSA encrypt and decrypt byte data. Swift

func chilkatTest() {
    var success: Bool = false

    // 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.
    success = 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.usePublicKey(pubKey: 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(numBytes: 32)

    var encBytes: NSData
    encBytes = rsa.encryptBytes(bData: keyBytes, bUsePrivateKey: false)

    // ------------------------------------------------------------------------------------------------------------------------
    // 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(path: "qa_data/rsaKeys/myTestRsaPrivate.pem", password: password)
    if success == false {
        print("\(privKey.lastErrorText!)")
        return
    }

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

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

    print("Success.")

}