| // 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.config.internal.TinkFipsUtil; |
| import com.google.crypto.tink.internal.KeyTypeManager; |
| import com.google.crypto.tink.internal.PrimitiveFactory; |
| import com.google.crypto.tink.proto.AesGcmKey; |
| import com.google.crypto.tink.proto.AesGcmKeyFormat; |
| import com.google.crypto.tink.proto.KeyData.KeyMaterialType; |
| import com.google.crypto.tink.subtle.AesGcmJce; |
| import com.google.crypto.tink.subtle.Random; |
| import com.google.crypto.tink.subtle.Validators; |
| 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 key manager generates new {@code AesGcmKey} keys and produces new instances of {@code |
| * AesGcmJce}. |
| */ |
| public final class AesGcmKeyManager extends KeyTypeManager<AesGcmKey> { |
| AesGcmKeyManager() { |
| super( |
| AesGcmKey.class, |
| new PrimitiveFactory<Aead, AesGcmKey>(Aead.class) { |
| @Override |
| public Aead getPrimitive(AesGcmKey key) throws GeneralSecurityException { |
| return new AesGcmJce(key.getKeyValue().toByteArray()); |
| } |
| }); |
| } |
| |
| @Override |
| public String getKeyType() { |
| return "type.googleapis.com/google.crypto.tink.AesGcmKey"; |
| } |
| |
| @Override |
| public int getVersion() { |
| return 0; |
| } |
| |
| @Override |
| public KeyMaterialType keyMaterialType() { |
| return KeyMaterialType.SYMMETRIC; |
| } |
| |
| @Override |
| public void validateKey(AesGcmKey key) throws GeneralSecurityException { |
| Validators.validateVersion(key.getVersion(), getVersion()); |
| Validators.validateAesKeySize(key.getKeyValue().size()); |
| } |
| |
| @Override |
| public AesGcmKey parseKey(ByteString byteString) throws InvalidProtocolBufferException { |
| return AesGcmKey.parseFrom(byteString, ExtensionRegistryLite.getEmptyRegistry()); |
| } |
| |
| @Override |
| public KeyFactory<AesGcmKeyFormat, AesGcmKey> keyFactory() { |
| return new KeyFactory<AesGcmKeyFormat, AesGcmKey>(AesGcmKeyFormat.class) { |
| @Override |
| public void validateKeyFormat(AesGcmKeyFormat format) throws GeneralSecurityException { |
| Validators.validateAesKeySize(format.getKeySize()); |
| } |
| |
| @Override |
| public AesGcmKeyFormat parseKeyFormat(ByteString byteString) |
| throws InvalidProtocolBufferException { |
| return AesGcmKeyFormat.parseFrom(byteString, ExtensionRegistryLite.getEmptyRegistry()); |
| } |
| |
| @Override |
| public AesGcmKey createKey(AesGcmKeyFormat format) throws GeneralSecurityException { |
| return AesGcmKey.newBuilder() |
| .setKeyValue(ByteString.copyFrom(Random.randBytes(format.getKeySize()))) |
| .setVersion(getVersion()) |
| .build(); |
| } |
| |
| @Override |
| public AesGcmKey deriveKey(AesGcmKeyFormat format, InputStream inputStream) |
| throws GeneralSecurityException { |
| Validators.validateVersion(format.getVersion(), getVersion()); |
| |
| byte[] pseudorandomness = new byte[format.getKeySize()]; |
| try { |
| int read = inputStream.read(pseudorandomness); |
| if (read != format.getKeySize()) { |
| throw new GeneralSecurityException("Not enough pseudorandomness given"); |
| } |
| return AesGcmKey.newBuilder() |
| .setKeyValue(ByteString.copyFrom(pseudorandomness)) |
| .setVersion(getVersion()) |
| .build(); |
| } catch (IOException e) { |
| throw new GeneralSecurityException("Reading pseudorandomness failed", e); |
| } |
| } |
| |
| @Override |
| public Map<String, KeyFactory.KeyFormat<AesGcmKeyFormat>> keyFormats() |
| throws GeneralSecurityException { |
| Map<String, KeyFactory.KeyFormat<AesGcmKeyFormat>> result = new HashMap<>(); |
| result.put("AES128_GCM", createKeyFormat(16, KeyTemplate.OutputPrefixType.TINK)); |
| result.put("AES128_GCM_RAW", createKeyFormat(16, KeyTemplate.OutputPrefixType.RAW)); |
| result.put("AES256_GCM", createKeyFormat(32, KeyTemplate.OutputPrefixType.TINK)); |
| result.put("AES256_GCM_RAW", createKeyFormat(32, KeyTemplate.OutputPrefixType.RAW)); |
| return Collections.unmodifiableMap(result); |
| } |
| }; |
| } |
| |
| public static void register(boolean newKeyAllowed) throws GeneralSecurityException { |
| Registry.registerKeyManager(new AesGcmKeyManager(), newKeyAllowed); |
| } |
| |
| /** |
| * @return a {@link KeyTemplate} that generates new instances of AES-GCM with the following |
| * parameters: |
| * <ul> |
| * <li>Key size: 16 bytes |
| * <li>Prefix type: {@link KeyTemplate.OutputPrefixType#TINK} |
| * </ul> |
| * <p>On Android KitKat (API level 19), the {@link com.google.crypto.tink.Aead} instance |
| * generated by this key template does not support associated data. It might not work at all |
| * in older versions. |
| * @deprecated use {@code KeyTemplates.get("AES128_GCM")} |
| */ |
| @Deprecated |
| public static final KeyTemplate aes128GcmTemplate() { |
| return createKeyTemplate(16, KeyTemplate.OutputPrefixType.TINK); |
| } |
| |
| /** |
| * @return a {@link KeyTemplate} that generates new instances of AES-GCM with the following |
| * parameters: |
| * <ul> |
| * <li>Key size: 16 bytes |
| * <li>Prefix type: {@link KeyTemplate.OutputPrefixType#RAW} (no prefix) |
| * </ul> |
| * <p>Keys generated from this template should create ciphertexts compatible with other |
| * libraries. |
| * <p>On Android KitKat (API level 19), the {@link com.google.crypto.tink.Aead} instance |
| * generated by this key template does not support associated data. It might not work at all |
| * in older versions. |
| * @deprecated use {@code KeyTemplates.get("AES128_GCM_RAW")} |
| */ |
| @Deprecated |
| public static final KeyTemplate rawAes128GcmTemplate() { |
| return createKeyTemplate(16, KeyTemplate.OutputPrefixType.RAW); |
| } |
| |
| /** |
| * @return a {@link KeyTemplate} that generates new instances of AES-GCM with the following |
| * parameters: |
| * <ul> |
| * <li>Key size: 32 bytes |
| * <li>Prefix type: {@link KeyTemplate.OutputPrefixType#TINK} |
| * </ul> |
| * <p>On Android KitKat (API level 19), the {@link com.google.crypto.tink.Aead} instance |
| * generated by this key template does not support associated data. It might not work at all |
| * in older versions. |
| * @deprecated use {@code KeyTemplates.get("AES256_GCM")} |
| */ |
| @Deprecated |
| public static final KeyTemplate aes256GcmTemplate() { |
| return createKeyTemplate(32, KeyTemplate.OutputPrefixType.TINK); |
| } |
| |
| /** |
| * @return a {@link KeyTemplate} that generates new instances of AES-GCM with the following |
| * parameters: |
| * <ul> |
| * <li>Key size: 32 bytes |
| * <li>Prefix type: {@link KeyTemplate.OutputPrefixType#RAW} (no prefix) |
| * </ul> |
| * <p>Keys generated from this template should create ciphertexts compatible with other |
| * libraries. |
| * <p>On Android KitKat (API level 19), the {@link com.google.crypto.tink.Aead} instance |
| * generated by this key template does not support associated data. It might not work at all |
| * in older versions. |
| * @deprecated use {@code KeyTemplates.get("AES256_GCM_RAW")} |
| */ |
| @Deprecated |
| public static final KeyTemplate rawAes256GcmTemplate() { |
| return createKeyTemplate(32, KeyTemplate.OutputPrefixType.RAW); |
| } |
| |
| /** |
| * @return a {@link KeyTemplate} containing a {@link AesGcmKeyFormat} with some specified |
| * parameters. |
| */ |
| private static KeyTemplate createKeyTemplate( |
| int keySize, KeyTemplate.OutputPrefixType prefixType) { |
| AesGcmKeyFormat format = AesGcmKeyFormat.newBuilder().setKeySize(keySize).build(); |
| return KeyTemplate.create( |
| new AesGcmKeyManager().getKeyType(), format.toByteArray(), prefixType); |
| } |
| |
| private static KeyFactory.KeyFormat<AesGcmKeyFormat> createKeyFormat( |
| int keySize, KeyTemplate.OutputPrefixType prefixType) { |
| AesGcmKeyFormat format = AesGcmKeyFormat.newBuilder().setKeySize(keySize).build(); |
| return new KeyFactory.KeyFormat<>(format, prefixType); |
| } |
| |
| @Override |
| public TinkFipsUtil.AlgorithmFipsCompatibility fipsStatus() { |
| return TinkFipsUtil.AlgorithmFipsCompatibility.ALGORITHM_REQUIRES_BORINGCRYPTO; |
| }; |
| } |