1 // Copyright 2022 Google LLC 2 // 3 // Licensed under the Apache License, Version 2.0 (the "License"); 4 // you may not use this file except in compliance with the License. 5 // You may obtain a copy of the License at 6 // 7 // http://www.apache.org/licenses/LICENSE-2.0 8 // 9 // Unless required by applicable law or agreed to in writing, software 10 // distributed under the License is distributed on an "AS IS" BASIS, 11 // WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. 12 // See the License for the specific language governing permissions and 13 // limitations under the License. 14 // 15 /////////////////////////////////////////////////////////////////////////////// 16 17 package com.google.crypto.tink.hybrid.internal; 18 19 import com.google.crypto.tink.proto.HpkePrivateKey; 20 import java.security.GeneralSecurityException; 21 22 /** Helper class for creating HPKE KEM asymmetric keys. */ 23 final class HpkeKemKeyFactory { 24 createPrivate(HpkePrivateKey privateKey)25 static HpkeKemPrivateKey createPrivate(HpkePrivateKey privateKey) 26 throws GeneralSecurityException { 27 switch (privateKey.getPublicKey().getParams().getKem()) { 28 case DHKEM_X25519_HKDF_SHA256: 29 return X25519HpkeKemPrivateKey.fromBytes(privateKey.getPrivateKey().toByteArray()); 30 case DHKEM_P256_HKDF_SHA256: 31 case DHKEM_P384_HKDF_SHA384: 32 case DHKEM_P521_HKDF_SHA512: 33 return NistCurvesHpkeKemPrivateKey.fromBytes( 34 privateKey.getPrivateKey().toByteArray(), 35 privateKey.getPublicKey().getPublicKey().toByteArray(), 36 HpkeUtil.nistHpkeKemToCurve(privateKey.getPublicKey().getParams().getKem())); 37 default: 38 throw new GeneralSecurityException("Unrecognized HPKE KEM identifier"); 39 } 40 } 41 HpkeKemKeyFactory()42 private HpkeKemKeyFactory() {} 43 } 44