StringEncrypt.kt

const val ENCRYPT_ALGORITHM = "AES"
fun String.encrypt(key: String): String {
    val keySpec = SecretKeySpec(key.toByteArray(Charsets.UTF_8), ENCRYPT_ALGORITHM)
    val iv = SecureRandom().generateSeed(keySpec.encoded.size)
    val encrypted = Cipher.getInstance("$ENCRYPT_ALGORITHM/CBC/PKCS5PADDING").run {
        init(Cipher.ENCRYPT_MODE, keySpec, IvParameterSpec(iv))
        doFinal([email protected](Charsets.UTF_8))
    }

    return "${hex(iv)}/${hex(encrypted)}"
}

fun String.decrypt(key: String): String {
    val keySpec = SecretKeySpec(key.toByteArray(), ENCRYPT_ALGORITHM)
    val iv = hex(substringBefore("/"))
    val encrypted = hex(substringAfter("/"))

    return Cipher.getInstance("$ENCRYPT_ALGORITHM/CBC/PKCS5PADDING").run {
        init(Cipher.DECRYPT_MODE, keySpec, IvParameterSpec(iv))
        doFinal(encrypted)
    }.toString(Charsets.UTF_8)
}