| // Copyright 2021 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 com.google.crypto.tink.hybrid.internal; |
| |
| import com.google.errorprone.annotations.Immutable; |
| import java.security.GeneralSecurityException; |
| |
| /** |
| * Interface for Hybrid Public Key Encryption (HPKE) key encapsulation mechanism (KEM). |
| * |
| * <p>HPKE RFC is available at https://www.rfc-editor.org/rfc/rfc9180.html. |
| */ |
| @Immutable |
| interface HpkeKem { |
| /** |
| * Generates and encapsulates a shared secret using the {@code recipientPublicKey}. Returns a |
| * {@link com.google.crypto.tink.hybrid.internal.HpkeKemEncapOutput} object that contains the raw |
| * shared secret and the encapsulated key. The HPKE RFC refers to this method as Encap(), which is |
| * used by the sender. |
| * |
| * @throws GeneralSecurityException when either the shared secret cannot be generated or the |
| * shared secret cannot be encapsulated. |
| */ |
| HpkeKemEncapOutput encapsulate(byte[] recipientPublicKey) throws GeneralSecurityException; |
| |
| /** |
| * Extracts the shared secret from {@code encapsulatedKey} using {@code recipientPrivateKey}. |
| * Returns the raw shared secret. The HPKE RFC refers to this method as Decap(), which is used |
| * by the recipient. |
| * |
| * @throws GeneralSecurityException if the shared secret cannot be extracted. |
| */ |
| byte[] decapsulate(byte[] encapsulatedKey, HpkeKemPrivateKey recipientPrivateKey) |
| throws GeneralSecurityException; |
| |
| /** |
| * Returns the HPKE KEM algorithm identifier for the underlying KEM implementation. |
| * |
| * <p>More details at |
| * https://www.rfc-editor.org/rfc/rfc9180.html#name-key-encapsulation-mechanism. |
| */ |
| byte[] getKemId() throws GeneralSecurityException; |
| } |