java/src/main/java/com/google/crypto/tink/PrivateKeyManagerImpl.java

// 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;

import com.google.crypto.tink.annotations.Alpha;
import com.google.crypto.tink.proto.KeyData;
import com.google.protobuf.ByteString;
import com.google.protobuf.InvalidProtocolBufferException;
import com.google.protobuf.MessageLite;
import java.security.GeneralSecurityException;

/**
 * Implementation of the {@link PrivateKeyManager} interface based on an {@link
 * PrivateKeyTypeManager} and the corresponding public key manager, implemented by an {@link
 * KeyTypeManager}.
 *
 * <p>Choosing {@code PrimitiveT} equal to {@link java.lang.Void} is valid; in this case the
 * functions {@link #getPrimitive} will throw if invoked.
 * TODO(tholenst) Reduce visibility to package visible once all managers have been migrated.
 */
@Alpha
public class PrivateKeyManagerImpl<
        PrimitiveT, KeyProtoT extends MessageLite, PublicKeyProtoT extends MessageLite>
    extends KeyManagerImpl<PrimitiveT, KeyProtoT> implements PrivateKeyManager<PrimitiveT> {

  private final PrivateKeyTypeManager<KeyProtoT, PublicKeyProtoT> privateKeyManager;
  private final KeyTypeManager<PublicKeyProtoT> publicKeyManager;

  public PrivateKeyManagerImpl(
      PrivateKeyTypeManager<KeyProtoT, PublicKeyProtoT> privateKeyManager,
      KeyTypeManager<PublicKeyProtoT> publicKeyManager,
      Class<PrimitiveT> primitiveClass) {
    super(privateKeyManager, primitiveClass);
    this.privateKeyManager = privateKeyManager;
    this.publicKeyManager = publicKeyManager;
  }

  @Override
  public KeyData getPublicKeyData(ByteString serializedKey) throws GeneralSecurityException {
    try {
      KeyProtoT privKeyProto = privateKeyManager.parseKey(serializedKey);
      privateKeyManager.validateKey(privKeyProto);
      PublicKeyProtoT publicKeyProto = privateKeyManager.getPublicKey(privKeyProto);
      publicKeyManager.validateKey(publicKeyProto);
      return KeyData.newBuilder()
          .setTypeUrl(publicKeyManager.getKeyType())
          .setValue(publicKeyProto.toByteString())
          .setKeyMaterialType(publicKeyManager.keyMaterialType())
          .build();
    } catch (InvalidProtocolBufferException e) {
      throw new GeneralSecurityException("expected serialized proto of type ", e);
    }
  }
}