1 /* 2 * Copyright (C) 2023 The Android Open Source Project 3 * 4 * Licensed under the Apache License, Version 2.0 (the "License"); 5 * you may not use this file except in compliance with the License. 6 * You may obtain a copy of the License at 7 * 8 * http://www.apache.org/licenses/LICENSE-2.0 9 * 10 * Unless required by applicable law or agreed to in writing, software 11 * distributed under the License is distributed on an "AS IS" BASIS, 12 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. 13 * See the License for the specific language governing permissions and 14 * limitations under the License. 15 */ 16 17 package com.android.adservices.ohttp.algorithms; 18 19 import com.android.adservices.ohttp.ObliviousHttpKeyConfig; 20 21 import com.google.auto.value.AutoValue; 22 23 /** 24 * Holds the HPKE cipher suite supported by the {@link 25 * com.android.adservices.ohttp.ObliviousHttpClient} 26 */ 27 @AutoValue 28 public abstract class HpkeAlgorithmSpec { 29 /** Get the KEM algorithm from this HPKE algorithm suite */ kem()30 public abstract KemAlgorithmSpec kem(); 31 32 /** Get the KDF algorithm from this HPKE algorithm suite */ kdf()33 public abstract KdfAlgorithmSpec kdf(); 34 35 /** Get the AEAD algorithm from this HPKE algorithm suite */ aead()36 public abstract AeadAlgorithmSpec aead(); 37 create( KemAlgorithmSpec kem, KdfAlgorithmSpec kdf, AeadAlgorithmSpec aead)38 private static HpkeAlgorithmSpec create( 39 KemAlgorithmSpec kem, KdfAlgorithmSpec kdf, AeadAlgorithmSpec aead) { 40 return new AutoValue_HpkeAlgorithmSpec(kem, kdf, aead); 41 } 42 43 /** 44 * Create a {@link HpkeAlgorithmSpec} from the keyConfig and throw {@link 45 * UnsupportedHpkeAlgorithmException} if any of the algorithms are not supported 46 */ fromKeyConfig(ObliviousHttpKeyConfig obliviousHttpKeyConfig)47 public static HpkeAlgorithmSpec fromKeyConfig(ObliviousHttpKeyConfig obliviousHttpKeyConfig) 48 throws UnsupportedHpkeAlgorithmException { 49 KemAlgorithmSpec kem = KemAlgorithmSpec.get(obliviousHttpKeyConfig.kemId()); 50 KdfAlgorithmSpec kdf = KdfAlgorithmSpec.get(obliviousHttpKeyConfig.kdfId()); 51 AeadAlgorithmSpec aead = AeadAlgorithmSpec.get(obliviousHttpKeyConfig.aeadId()); 52 return create(kem, kdf, aead); 53 } 54 } 55