I’m implementing AES/GCM/NoPadding encryption in Swift for iOS with a minimum deployment target of 12.1. I’m trying to achieve similar functionality as my Java code below:

Cipher cipherAes = initCipher(Cipher.ENCRYPT_MODE, key, iv);
byte[] encryptedMessageByte = cipherAes.doFinal(messageBytes);

byte[] cipherByte = ByteBuffer.allocate(iv.length + salt.length + encryptedMessageByte.length)
        .put(iv)
        .put(salt)
        .put(encryptedMessageByte)
        .array();

In Swift, I’ve written the following code:

let gcm = GCM(iv: iv.bytes, additionalAuthenticatedData: nil, tagLength: tagLength)
let aes = try AES(key: key.bytes, blockMode: gcm, padding: .noPadding)
let encryptedMessage = try aes.encrypt(message.bytes)
let cipherData = Data(iv) + Data(salt) + Data(encryptedMessage)

However, the length of encryptedMessage in Swift differs from encryptedMessageByte in Java. I expected both to produce ciphertext of similar lengths.

Assurance:
I’m sure that the lengths of key, iv, and salt are the same in both Java and Swift implementations.

Question:
Are there any additional configurations or parameters needed for AES/GCM/NoPadding encryption in Swift to match the behavior in Java?