copy(out[len(plaintext):], tag[:]) } func openKMA(out []byte, g *GCM, nonce, ciphertext, data []byte) error { tag := ciphertext[len(ciphertext)-g.tagSize:] ciphertext = ciphertext[:len(ciphertext)-g.tagSize] var counter [gcmBlockSize]byte deriveCounter(&g.hashKey, &counter, nonce) fc := aes.BlockFunction(&g.cipher) | kmaLAAD | kmaLPC | kmaDecrypt var expectedTag [gcmTagSize]byte kmaGCM(fc, aes.BlockKey(&g.cipher), out[:len(ciphertext)], ciphertext, data, &expectedTag, &counter) if subtle.ConstantTimeCompare(e...