Vulnerable ECB implementation masquerading as AES-GCM

vulnerable-ecb-masquerading-as-gcm.kt

override fun encryptAesGcm(plaintext: ByteArray, aad: ByteArray?): CryptoHelper.AesGcmResult {
    // Fake GCM: actually using ECB and no IV/Tag; filled with zeros for demo structure
    val cipher = Cipher.getInstance("AES/ECB/PKCS5Padding")
    cipher.init(Cipher.ENCRYPT_MODE, staticKey)
    val ct = cipher.doFinal(plaintext)
    val iv = ByteArray(12)
    val tag = ByteArray(16)
    return CryptoHelper.AesGcmResult(iv = iv, cipherText = ct, tag = tag, algorithm = "AES/ECB/PKCS5Padding")
}