Swift

Streaming Encryption by Encrypting in Chunks

See more Encryption Examples

Encrypt data in chunks. Swift

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

    let crypt = CkoCrypt2()!

    crypt.cryptAlgorithm = "aes"
    crypt.cipherMode = "cbc"
    crypt.keyLength = 128

    crypt.setEncodedKey(keyStr: "000102030405060708090A0B0C0D0E0F", encoding: "hex")
    crypt.setEncodedIV(ivStr: "000102030405060708090A0B0C0D0E0F", encoding: "hex")

    crypt.encodingMode = "hex"
    var txt1: String? = "The quick brown fox jumped over the lazy dog.\r\n"
    var txt2: String? = "-\r\n"
    var txt3: String? = "Done.\r\n"

    let sbEncrypted = CkoStringBuilder()!

    // Encrypt the 1st chunk:
    // (don't worry about feeding the data to the encryptor in 
    // exact multiples of the encryption algorithm's block size.
    // Chilkat will buffer the data.)
    crypt.firstChunk = true
    crypt.lastChunk = false
    sbEncrypted.append(value: crypt.encryptStringENC(str: txt1))

    // Encrypt the 2nd chunk
    crypt.firstChunk = false
    crypt.lastChunk = false
    sbEncrypted.append(value: crypt.encryptStringENC(str: txt2))

    // Now encrypt N more chunks...
    // Remember -- we're doing this in CBC mode, so each call
    // to the encrypt method depends on the state from previous
    // calls...
    crypt.firstChunk = false
    crypt.lastChunk = false
    var i: Int
    for i = 0; i <= 4; i++ {
        sbEncrypted.append(value: crypt.encryptStringENC(str: txt1))
        sbEncrypted.append(value: crypt.encryptStringENC(str: txt2))
    }

    // Now encrypt the last chunk:
    crypt.firstChunk = false
    crypt.lastChunk = true
    sbEncrypted.append(value: crypt.encryptStringENC(str: txt3))

    print("\(sbEncrypted.getAsString()!)")

    // Now decrypt in one call.
    // (The data we're decrypting is both the first AND last chunk.)  
    crypt.firstChunk = true
    crypt.lastChunk = true
    var decryptedText: String? = crypt.decryptStringENC(str: sbEncrypted.getAsString())

    print("\(decryptedText!)")

    // Note: You may decrypt in N chunks by setting the FirstChunk
    // and LastChunk properties prior to calling the Decrypt* methods

}