| // 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 derivation function (KDF). |
| * |
| * <p>HPKE RFC is available at https://www.rfc-editor.org/rfc/rfc9180.html. |
| */ |
| @Immutable |
| interface HpkeKdf { |
| /** |
| * Extracts pseudorandom key from {@code salt} and {@code ikm} using the HPKE-specific values |
| * {@code ikmLabel} and {@code suiteId} to facilitate domain separation and context binding. |
| * |
| * <p>More details available at https://www.rfc-editor.org/rfc/rfc9180.html#section-4-9. |
| * |
| * @param salt optional (possibly non-secret) random value |
| * @param ikm input keying material |
| * @param ikmLabel label prepended to {@code ikm} |
| * @param suiteId HPKE cipher suite identifier prepended to { {@code ikmLabel} || {@code ikm} } |
| * @return pseudorandom key |
| */ |
| byte[] labeledExtract(byte[] salt, byte[] ikm, String ikmLabel, byte[] suiteId) |
| throws GeneralSecurityException; |
| |
| /** |
| * Expands pseudorandom key {@code prk} into {@code length} pseudorandom bytes using {@code info} |
| * along with the HPKE-specific values {@code infoLabel} and {@code suiteId} to facilitate domain |
| * separation and context binding. |
| * |
| * <p>More details available at https://www.rfc-editor.org/rfc/rfc9180.html#section-4-10. |
| * |
| * @param prk pseudorandom key |
| * @param info optional context and application-specific information |
| * @param infoLabel label prepended to {@code info} |
| * @param suiteId HPKE cipher suite identifier prepended to { {@code infoLabel} || {@code info} } |
| * @param length desired length (in bytes) of pseudorandom output |
| * @return {@code length} pseudorandom bytes of output keying material |
| */ |
| byte[] labeledExpand(byte[] prk, byte[] info, String infoLabel, byte[] suiteId, int length) |
| throws GeneralSecurityException; |
| |
| /** |
| * Combines {@link #labeledExtract(byte[], byte[], String, byte[])} and {@link |
| * #labeledExpand(byte[], byte[], String, byte[], int)} into a single method. |
| * |
| * <p>More details available at https://www.rfc-editor.org/rfc/rfc9180.html#section-4.1-3. |
| * |
| * @param salt optional (possibly non-secret) random value |
| * @param ikm input keying material |
| * @param ikmLabel label prepended to {@code ikm} |
| * @param info optional context and application-specific information |
| * @param infoLabel label prepended to {@code info} |
| * @param suiteId HPKE cipher suite identifier prepended to { {@code ikmLabel} || {@code ikm} } |
| * and { {@code infoLabel} || {@code info} } |
| * @param length desired length (in bytes) of pseudorandom output |
| * @return {@code length} pseudorandom bytes of output keying material |
| */ |
| byte[] extractAndExpand( |
| byte[] salt, |
| byte[] ikm, |
| String ikmLabel, |
| byte[] info, |
| String infoLabel, |
| byte[] suiteId, |
| int length) |
| throws GeneralSecurityException; |
| |
| /** |
| * Returns the HPKE KDF algorithm identifier for the underlying KDF implementation. |
| * |
| * <p>More details at |
| * https://www.rfc-editor.org/rfc/rfc9180.html#name-key-derivation-functions-kd. |
| */ |
| byte[] getKdfId() throws GeneralSecurityException; |
| } |