| // 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.aead; |
| |
| import com.google.crypto.tink.Aead; |
| import com.google.crypto.tink.KeyTemplate; |
| import com.google.crypto.tink.Registry; |
| import com.google.crypto.tink.internal.KeyTypeManager; |
| import com.google.crypto.tink.internal.PrimitiveFactory; |
| import com.google.crypto.tink.proto.KeyData.KeyMaterialType; |
| import com.google.crypto.tink.proto.XChaCha20Poly1305Key; |
| import com.google.crypto.tink.proto.XChaCha20Poly1305KeyFormat; |
| import com.google.crypto.tink.subtle.Random; |
| import com.google.crypto.tink.subtle.Validators; |
| import com.google.crypto.tink.subtle.XChaCha20Poly1305; |
| import com.google.protobuf.ByteString; |
| import com.google.protobuf.ExtensionRegistryLite; |
| import com.google.protobuf.InvalidProtocolBufferException; |
| import java.io.IOException; |
| import java.io.InputStream; |
| import java.security.GeneralSecurityException; |
| import java.util.Collections; |
| import java.util.HashMap; |
| import java.util.Map; |
| |
| /** |
| * This instance of {@code KeyManager} generates new {@code XChaCha20Poly1305} keys and produces new |
| * instances of {@code XChaCha20Poly1305}. |
| */ |
| public class XChaCha20Poly1305KeyManager extends KeyTypeManager<XChaCha20Poly1305Key> { |
| XChaCha20Poly1305KeyManager() { |
| super( |
| XChaCha20Poly1305Key.class, |
| new PrimitiveFactory<Aead, XChaCha20Poly1305Key>(Aead.class) { |
| @Override |
| public Aead getPrimitive(XChaCha20Poly1305Key key) throws GeneralSecurityException { |
| return new XChaCha20Poly1305(key.getKeyValue().toByteArray()); |
| } |
| }); |
| } |
| |
| private static final int KEY_SIZE_IN_BYTES = 32; |
| |
| @Override |
| public String getKeyType() { |
| return "type.googleapis.com/google.crypto.tink.XChaCha20Poly1305Key"; |
| } |
| |
| @Override |
| public int getVersion() { |
| return 0; |
| } |
| |
| @Override |
| public KeyMaterialType keyMaterialType() { |
| return KeyMaterialType.SYMMETRIC; |
| } |
| |
| @Override |
| public void validateKey(XChaCha20Poly1305Key key) throws GeneralSecurityException { |
| Validators.validateVersion(key.getVersion(), getVersion()); |
| if (key.getKeyValue().size() != KEY_SIZE_IN_BYTES) { |
| throw new GeneralSecurityException("invalid XChaCha20Poly1305Key: incorrect key length"); |
| } |
| } |
| |
| @Override |
| public XChaCha20Poly1305Key parseKey(ByteString byteString) |
| throws InvalidProtocolBufferException { |
| return XChaCha20Poly1305Key.parseFrom(byteString, ExtensionRegistryLite.getEmptyRegistry()); |
| } |
| |
| @Override |
| public KeyFactory<XChaCha20Poly1305KeyFormat, XChaCha20Poly1305Key> keyFactory() { |
| return new KeyFactory<XChaCha20Poly1305KeyFormat, XChaCha20Poly1305Key>( |
| XChaCha20Poly1305KeyFormat.class) { |
| @Override |
| public void validateKeyFormat(XChaCha20Poly1305KeyFormat format) |
| throws GeneralSecurityException {} |
| |
| @Override |
| public XChaCha20Poly1305KeyFormat parseKeyFormat(ByteString byteString) |
| throws InvalidProtocolBufferException { |
| return XChaCha20Poly1305KeyFormat.parseFrom( |
| byteString, ExtensionRegistryLite.getEmptyRegistry()); |
| } |
| |
| @Override |
| public XChaCha20Poly1305Key createKey(XChaCha20Poly1305KeyFormat format) |
| throws GeneralSecurityException { |
| return XChaCha20Poly1305Key.newBuilder() |
| .setVersion(getVersion()) |
| .setKeyValue(ByteString.copyFrom(Random.randBytes(KEY_SIZE_IN_BYTES))) |
| .build(); |
| } |
| |
| @Override |
| public XChaCha20Poly1305Key deriveKey( |
| XChaCha20Poly1305KeyFormat format, InputStream inputStream) |
| throws GeneralSecurityException { |
| Validators.validateVersion(format.getVersion(), getVersion()); |
| |
| byte[] pseudorandomness = new byte[KEY_SIZE_IN_BYTES]; |
| try { |
| int read = inputStream.read(pseudorandomness); |
| if (read != KEY_SIZE_IN_BYTES) { |
| throw new GeneralSecurityException("Not enough pseudorandomness given"); |
| } |
| return XChaCha20Poly1305Key.newBuilder() |
| .setKeyValue(ByteString.copyFrom(pseudorandomness)) |
| .setVersion(getVersion()) |
| .build(); |
| } catch (IOException e) { |
| throw new GeneralSecurityException("Reading pseudorandomness failed", e); |
| } |
| } |
| |
| @Override |
| public Map<String, KeyFactory.KeyFormat<XChaCha20Poly1305KeyFormat>> keyFormats() |
| throws GeneralSecurityException { |
| Map<String, KeyFactory.KeyFormat<XChaCha20Poly1305KeyFormat>> result = new HashMap<>(); |
| result.put( |
| "XCHACHA20_POLY1305", |
| new KeyFactory.KeyFormat<>( |
| XChaCha20Poly1305KeyFormat.getDefaultInstance(), |
| KeyTemplate.OutputPrefixType.TINK)); |
| result.put( |
| "XCHACHA20_POLY1305_RAW", |
| new KeyFactory.KeyFormat<>( |
| XChaCha20Poly1305KeyFormat.getDefaultInstance(), KeyTemplate.OutputPrefixType.RAW)); |
| return Collections.unmodifiableMap(result); |
| } |
| }; |
| } |
| |
| public static void register(boolean newKeyAllowed) throws GeneralSecurityException { |
| Registry.registerKeyManager(new XChaCha20Poly1305KeyManager(), newKeyAllowed); |
| } |
| |
| /** |
| * @return a {@link KeyTemplate} that generates new instances of XChaCha20Poly1305 keys. |
| * @deprecated use {@code KeyTemplates.get("XCHACHA20_POLY1305")} |
| */ |
| @Deprecated |
| public static final KeyTemplate xChaCha20Poly1305Template() { |
| return KeyTemplate.create( |
| new XChaCha20Poly1305KeyManager().getKeyType(), |
| XChaCha20Poly1305KeyFormat.getDefaultInstance().toByteArray(), |
| KeyTemplate.OutputPrefixType.TINK); |
| } |
| |
| /** |
| * @return a {@link KeyTemplate} that generates new instances of XChaCha20Poly1305 keys. Keys |
| * generated from this template create ciphertexts compatible with libsodium and other |
| * libraries. |
| * @deprecated use {@code KeyTemplates.get("XCHACHA20_POLY1305_RAW")} |
| */ |
| @Deprecated |
| public static final KeyTemplate rawXChaCha20Poly1305Template() { |
| return KeyTemplate.create( |
| new XChaCha20Poly1305KeyManager().getKeyType(), |
| XChaCha20Poly1305KeyFormat.getDefaultInstance().toByteArray(), |
| KeyTemplate.OutputPrefixType.RAW); |
| } |
| } |