| // Copyright 2018 Google LLC |
| // |
| // Licensed under the Apache License, Version 2.0 (the "License"); |
| // you may not use this file except in compliance with the License. |
| // You may obtain a copy of the License at |
| // |
| // http://www.apache.org/licenses/LICENSE-2.0 |
| // |
| // Unless required by applicable law or agreed to in writing, software |
| // distributed under the License is distributed on an "AS IS" BASIS, |
| // WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. |
| // See the License for the specific language governing permissions and |
| // limitations under the License. |
| |
| package tink |
| |
| /* |
| DeterministicAEAD is the interface for deterministic authenticated encryption with associated data. |
| |
| Warning: |
| Unlike AEAD, implementations of this interface are not semantically secure, because |
| encrypting the same plaintext always yields the same ciphertext. |
| |
| Security guarantees: |
| Implementations of this interface provide 128-bit security level against multi-user attacks |
| with up to 2^32 keys. That means if an adversary obtains 2^32 ciphertexts of the same message |
| encrypted under 2^32 keys, they need to do 2^128 computations to obtain a single key. |
| |
| Encryption with associated data ensures authenticity (who the sender is) and integrity (the |
| data has not been tampered with) of that data, but not its secrecy. |
| |
| References: |
| * https://tools.ietf.org/html/rfc5116 |
| * https://tools.ietf.org/html/rfc5297#section-1.3 |
| */ |
| type DeterministicAEAD interface { |
| // EncryptDeterministically deterministically encrypts plaintext with associatedData as |
| // associated authenticated data. |
| // |
| // Warning: |
| // Encrypting the same plaintext multiple times protects the integrity of that plaintext, |
| // but confidentiality is compromised to the extent that an attacker can determine that |
| // the same plaintext was encrypted. |
| // |
| // The resulting ciphertext allows for checking authenticity and integrity of associatedData, |
| // but does not guarantee its secrecy. |
| EncryptDeterministically(plaintext, associatedData []byte) ([]byte, error) |
| |
| // DecryptDeterministically deterministically decrypts ciphertext with associatedData as |
| // associated authenticated data. The decryption verifies the authenticity and integrity |
| // of the associated data, but there are no guarantees with respect to secrecy of that data. |
| DecryptDeterministically(ciphertext, associatedData []byte) ([]byte, error) |
| } |