| // Copyright 2017 Google Inc. |
| // |
| // 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; |
| |
| import com.google.crypto.tink.HybridEncrypt; |
| import com.google.crypto.tink.PrimitiveSet; |
| import com.google.crypto.tink.PrimitiveWrapper; |
| import com.google.crypto.tink.Registry; |
| import com.google.crypto.tink.subtle.Bytes; |
| import java.security.GeneralSecurityException; |
| |
| /** |
| * The implementation of {@code PrimitiveWrapper<HybridEncrypt>}. |
| * |
| * <p>The returned primitive works with a keyset (rather than a single key). To encrypt a plaintext, |
| * it uses the primary key in the keyset, and prepends to the ciphertext a certain prefix associated |
| * with the primary key. |
| */ |
| public class HybridEncryptWrapper implements PrimitiveWrapper<HybridEncrypt, HybridEncrypt> { |
| private static class WrappedHybridEncrypt implements HybridEncrypt { |
| final PrimitiveSet<HybridEncrypt> primitives; |
| |
| public WrappedHybridEncrypt(final PrimitiveSet<HybridEncrypt> primitives) { |
| this.primitives = primitives; |
| } |
| |
| @Override |
| public byte[] encrypt(final byte[] plaintext, final byte[] contextInfo) |
| throws GeneralSecurityException { |
| if (primitives.getPrimary() == null) { |
| throw new GeneralSecurityException("keyset without primary key"); |
| } |
| return Bytes.concat( |
| primitives.getPrimary().getIdentifier(), |
| primitives.getPrimary().getPrimitive().encrypt(plaintext, contextInfo)); |
| } |
| } |
| |
| HybridEncryptWrapper() {} |
| |
| @Override |
| public HybridEncrypt wrap(final PrimitiveSet<HybridEncrypt> primitives) { |
| return new WrappedHybridEncrypt(primitives); |
| } |
| |
| @Override |
| public Class<HybridEncrypt> getPrimitiveClass() { |
| return HybridEncrypt.class; |
| } |
| |
| @Override |
| public Class<HybridEncrypt> getInputPrimitiveClass() { |
| return HybridEncrypt.class; |
| } |
| |
| /** |
| * Register the wrapper within the registry. |
| * |
| * <p>This is required for calls to {@link Keyset.getPrimitive} with a {@link HybridEncrypt} |
| * argument. |
| */ |
| public static void register() throws GeneralSecurityException { |
| Registry.registerPrimitiveWrapper(new HybridEncryptWrapper()); |
| } |
| } |