marcobrador

fun generateAesKey(): SecretKey {
    val keyGenerator = KeyGenerator.getInstance(KeyProperties.KEY_ALGORITHM_AES, "AndroidKeyStore")
    val kgps = KeyGenParameterSpec.Builder("my_aes_key", KeyProperties.PURPOSE_ENCRYPT or KeyProperties.PURPOSE_DECRYPT)
        .setBlockModes(KeyProperties.BLOCK_MODE_GCM)
        .setEncryptionPaddings(KeyProperties.ENCRYPTION_PADDING_NONE)
        // This is required to be able to provide the IV ourselves
        .setRandomizedEncryptionRequired(false)
        .build()
    keyGenerator.init(kgps)
    return keyGenerator.generateKey()

marcobrador

const val TAG_LENGTH = 16

class EncryptionOutput(val tag: ByteArray,
                       val ciphertext: ByteArray)

fun encrypt(key: SecretKey, iv: ByteArray, aad: ByteArray, message: ByteArray): EncryptionOutput {
    val cipher = Cipher.getInstance("AES/GCM/NoPadding")
    val spec = GCMParameterSpec(TAG_LENGTH * 8, iv)
    cipher.init(Cipher.ENCRYPT_MODE, key, spec)
    cipher.updateAAD(aad)

marcobrador

const val AAD_LENGTH = 16
const val TAG_LENGTH = 16

class EncryptionOutput(val iv: ByteArray,
                       val aad: ByteArray,
                       val tag: ByteArray,
                       val ciphertext: ByteArray)

fun encrypt(key: SecretKey, message: ByteArray): EncryptionOutput {
    val cipher = Cipher.getInstance("AES/GCM/NoPadding")

marcobrador

const val TAG_LENGTH = 16

class EncryptionOutput(val iv: ByteArray,
                       val tag: ByteArray,
                       val ciphertext: ByteArray)

fun encrypt(key: SecretKey, message: ByteArray): EncryptionOutput {
    val cipher = Cipher.getInstance("AES/GCM/NoPadding")
    cipher.init(Cipher.ENCRYPT_MODE, key)
    val iv = cipher.iv.copyOf()

marcobrador

const val TAG_LENGTH = 16

fun encrypt(key: SecretKey, message: ByteArray): Pair<ByteArray, ByteArray> {
    val cipher = Cipher.getInstance("AES/GCM/NoPadding")
    cipher.init(Cipher.ENCRYPT_MODE, key)
    val iv = cipher.iv.copyOf()
    val ciphertext = cipher.doFinal(message)
    return Pair(iv, ciphertext)
}