com.amazonaws.encryptionsdk.MasterKey Maven / Gradle / Ivy
/*
* Copyright 2016 Amazon.com, Inc. or its affiliates. All Rights Reserved.
*
* Licensed under the Apache License, Version 2.0 (the "License"). You may not use this file except
* in compliance with the License. A copy of the License is located at
*
* http://aws.amazon.com/apache2.0
*
* or in the "license" file accompanying this file. This file 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.amazonaws.encryptionsdk;
import java.util.Collections;
import java.util.List;
import java.util.Map;
import java.util.Objects;
import com.amazonaws.encryptionsdk.exception.NoSuchMasterKeyException;
import com.amazonaws.encryptionsdk.exception.UnsupportedProviderException;
/**
* Represents the cryptographic key used to protect the {@link DataKey} (which, in turn, protects
* the data).
*
* All MasterKeys extend {@link MasterKeyProvider} because they are all capable of providing exactly
* themselves. This simplifies implementation when only a single {@link MasterKey} is used and/or
* expected.
*
* @param
* the concrete type of the {@link MasterKey}
*/
public abstract class MasterKey> extends MasterKeyProvider {
public abstract String getProviderId();
/**
* Equivalent to calling {@link #getProviderId()}.
*/
@Override
public String getDefaultProviderId() {
return getProviderId();
}
public abstract String getKeyId();
/**
* Generates a new {@link DataKey} which is protected by this {@link MasterKey} for use with
* {@code algorithm} and associated with the provided {@code encryptionContext}.
*/
public abstract DataKey generateDataKey(CryptoAlgorithm algorithm, Map encryptionContext);
/**
* Returns a new copy of the provided {@code dataKey} which is protected by this
* {@link MasterKey} for use with {@code algorithm} and associated with the provided
* {@code encryptionContext}.
*/
public abstract DataKey encryptDataKey(CryptoAlgorithm algorithm, Map encryptionContext,
DataKey dataKey);
/**
* Returns {@code true} if and only if {@code provider} equals {@link #getProviderId()}.
*/
@Override
public boolean canProvide(final String provider) {
return getProviderId().equals(provider);
}
/**
* Returns {@code this} if {@code provider} and {@code keyId} match {@code this}. Otherwise,
* throws an appropriate exception.
*/
@SuppressWarnings("unchecked")
@Override
public K getMasterKey(final String provider, final String keyId) throws UnsupportedProviderException,
NoSuchMasterKeyException {
if (!canProvide(provider)) {
throw new UnsupportedProviderException("MasterKeys can only provide themselves. Requested "
+ buildName(provider, keyId) + " but only " + toString() + " is available");
}
if (!getKeyId().equals(keyId)) {
throw new NoSuchMasterKeyException("MasterKeys can only provide themselves. Requested "
+ buildName(provider, keyId) + " but only " + toString() + " is available");
}
return (K) this;
}
@Override
public String toString() {
return buildName(getProviderId(), getKeyId());
}
/**
* Returns a list of length {@code 1} containing {@code this}.
*/
@SuppressWarnings("unchecked")
@Override
public List getMasterKeysForEncryption(final MasterKeyRequest request) {
return (List) Collections.singletonList(this);
}
private static String buildName(final String provider, final String keyId) {
return String.format("%s://%s", provider, keyId);
}
/**
* Two {@link MasterKey}s are equal if they are instances of the exact same class and
* their values for {@code keyId}, {@code providerId}, and {@code defaultProviderId} are equal.
*/
@Override
public boolean equals(final Object obj) {
if (obj == null) {
return false;
}
if (this == obj) {
return true;
}
if (!obj.getClass().equals(getClass())) {
return false;
}
final MasterKey mk = (MasterKey) obj;
return Objects.equals(getKeyId(), mk.getKeyId()) &&
Objects.equals(getProviderId(), mk.getProviderId()) &&
Objects.equals(getDefaultProviderId(), mk.getDefaultProviderId());
}
@Override
public int hashCode() {
return Objects.hash(getKeyId(), getProviderId(), getDefaultProviderId());
}
}