com.google.crypto.tink.internal.PrimitiveSet Maven / Gradle / Ivy
Show all versions of tink Show documentation
// Copyright 2017 Google LLC
//
// 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.internal;
import com.google.crypto.tink.CryptoFormat;
import com.google.crypto.tink.Key;
import com.google.crypto.tink.Parameters;
import com.google.crypto.tink.proto.KeyStatusType;
import com.google.crypto.tink.proto.Keyset;
import com.google.crypto.tink.proto.OutputPrefixType;
import com.google.crypto.tink.util.Bytes;
import com.google.errorprone.annotations.CanIgnoreReturnValue;
import java.security.GeneralSecurityException;
import java.util.ArrayList;
import java.util.Collection;
import java.util.Collections;
import java.util.HashMap;
import java.util.List;
import java.util.Map;
import javax.annotation.Nullable;
/**
* A container class for a set of primitives -- implementations of cryptographic primitives offered
* by Tink.
*
* It provides also additional properties for the primitives it holds. In particular, one of the
* primitives in the set can be distinguished as "the primary" one.
*
*
PrimitiveSet is an auxiliary class used for supporting key rotation: primitives in a set
* correspond to keys in a keyset. Users will usually work with primitive instances, which
* essentially wrap primitive sets. For example an instance of an Aead-primitive for a given keyset
* holds a set of Aead-primitives corresponding to the keys in the keyset, and uses the set members
* to do the actual crypto operations: to encrypt data the primary Aead-primitive from the set is
* used, and upon decryption the ciphertext's prefix determines the id of the primitive from the
* set.
*/
public final class PrimitiveSet
{
/**
* A single entry in the set. In addition to the actual primitive it holds also some extra
* information about the primitive.
*/
public static final class Entry
{
// If set, this is a primitive of a key.
private final P fullPrimitive;
// Identifies the primitive within the set.
// It is the ciphertext prefix of the corresponding key.
private final Bytes outputPrefix;
// The status of the key represented by the primitive. Currently always equal to "ENABLED".
private final KeyStatusType status;
// The output prefix type of the key represented by the primitive.
private final OutputPrefixType outputPrefixType;
// The id of the key.
private final int keyId;
private final String keyTypeUrl;
private final Key key;
private Entry(
P fullPrimitive,
final Bytes outputPrefix,
KeyStatusType status,
OutputPrefixType outputPrefixType,
int keyId,
String keyTypeUrl,
Key key) {
this.fullPrimitive = fullPrimitive;
this.outputPrefix = outputPrefix;
this.status = status;
this.outputPrefixType = outputPrefixType;
this.keyId = keyId;
this.keyTypeUrl = keyTypeUrl;
this.key = key;
}
/**
* Returns the full primitive for this entry.
*
*
This is used in cases when the new Tink Key interface is used and the primitive is
* self-sufficient by itself, meaning that all the necessary information to process the
* primitive is contained in the primitive (most likely through the new Key interface), as
* opposed to the {@code primitive} field (see {@link #getPrimitive} for details).
*/
public P getFullPrimitive() {
return this.fullPrimitive;
}
public KeyStatusType getStatus() {
return status;
}
public OutputPrefixType getOutputPrefixType() {
return outputPrefixType;
}
private final Bytes getOutputPrefix() {
return outputPrefix;
}
public int getKeyId() {
return keyId;
}
public String getKeyTypeUrl() {
return keyTypeUrl;
}
public Key getKey() {
return key;
}
@Nullable
public Parameters getParameters() {
if (key == null) {
return null;
}
return key.getParameters();
}
}
private static
void storeEntryInPrimitiveSet(
Entry
entry, Map>> entries, List> entriesInKeysetOrder) {
List> list = new ArrayList<>();
list.add(entry);
List> existing =
entries.put(entry.getOutputPrefix(), Collections.unmodifiableList(list));
if (existing != null) {
List> newList = new ArrayList<>();
newList.addAll(existing);
newList.add(entry);
entries.put(entry.getOutputPrefix(), Collections.unmodifiableList(newList));
}
entriesInKeysetOrder.add(entry);
}
/** Returns the entry with the primary primitive. */
@Nullable
public Entry getPrimary() {
return primary;
}
public boolean hasAnnotations() {
return !annotations.toMap().isEmpty();
}
public MonitoringAnnotations getAnnotations() {
return annotations;
}
/** Returns all primitives using RAW prefix. */
public List> getRawPrimitives() {
return getPrimitive(CryptoFormat.RAW_PREFIX);
}
/** Returns the entries with primitive identifed by {@code identifier}. */
public List> getPrimitive(final byte[] identifier) {
List> found = entries.get(Bytes.copyFrom(identifier));
return found != null ? found : Collections.>emptyList();
}
/** Returns all primitives. */
public Collection>> getAll() {
return entries.values();
}
/** Returns all primitives in the original keyset key order. */
public List> getAllInKeysetOrder() {
return Collections.unmodifiableList(entriesInKeysetOrder);
}
/**
* The primitives are stored in a hash map of (ciphertext prefix, list of primitives sharing the
* prefix). This allows quickly retrieving the list of primitives sharing some particular prefix.
* Because all RAW keys are using an empty prefix, this also quickly allows retrieving them.
*/
private final Map>> entries;
/** Stores entries in the original keyset key order. */
private final List> entriesInKeysetOrder;
private final Entry primary;
private final Class
primitiveClass;
private final MonitoringAnnotations annotations;
/** Creates an immutable PrimitiveSet. It is used by the Builder. */
private PrimitiveSet(
Map>> entries,
List> entriesInKeysetOrder,
Entry primary,
MonitoringAnnotations annotations,
Class
primitiveClass) {
this.entries = entries;
this.entriesInKeysetOrder = entriesInKeysetOrder;
this.primary = primary;
this.primitiveClass = primitiveClass;
this.annotations = annotations;
}
public Class
getPrimitiveClass() {
return primitiveClass;
}
/** Builds an immutable PrimitiveSet. This is the prefered way to construct a PrimitiveSet. */
public static class Builder
{
private final Class
primitiveClass;
// primitives == null indicates that build has been called and the builder can't be used
// anymore.
private Map>> entries = new HashMap<>();
private final List> entriesInKeysetOrder = new ArrayList<>();
private Entry primary;
private MonitoringAnnotations annotations;
@CanIgnoreReturnValue
private Builder
addEntry(
final P fullPrimitive, Key key, Keyset.Key protoKey, boolean asPrimary)
throws GeneralSecurityException {
if (entries == null) {
throw new IllegalStateException("addEntry cannot be called after build");
}
if (fullPrimitive == null) {
throw new NullPointerException("`fullPrimitive` must not be null");
}
if (protoKey.getStatus() != KeyStatusType.ENABLED) {
throw new GeneralSecurityException("only ENABLED key is allowed");
}
Entry
entry =
new Entry
(
fullPrimitive,
Bytes.copyFrom(CryptoFormat.getOutputPrefix(protoKey)),
protoKey.getStatus(),
protoKey.getOutputPrefixType(),
protoKey.getKeyId(),
protoKey.getKeyData().getTypeUrl(),
key);
storeEntryInPrimitiveSet(entry, entries, entriesInKeysetOrder);
if (asPrimary) {
if (this.primary != null) {
throw new IllegalStateException("you cannot set two primary primitives");
}
this.primary = entry;
}
return this;
}
/**
* Adds a non-primary primitive.
*
*
The caller must make sure that the {@code fullPrimitive} is a full primitive constructed
* from key, and that {@code protoKey} contains the same key as {@code fullPrimitive}.
*/
@CanIgnoreReturnValue
public Builder
addFullPrimitive(final P fullPrimitive, Key key, Keyset.Key protoKey)
throws GeneralSecurityException {
return addEntry(fullPrimitive, key, protoKey, false);
}
/**
* Adds the primary primitive. This should be called exactly once per PrimitiveSet.
*
*
The caller must make sure that the {@code fullPrimitive} is a full primitive constructed
* from key, and that {@code protoKey} contains the same key as {@code fullPrimitive}.
*/
@CanIgnoreReturnValue
public Builder
addPrimaryFullPrimitive(final P fullPrimitive, Key key, Keyset.Key protoKey)
throws GeneralSecurityException {
return addEntry(fullPrimitive, key, protoKey, true);
}
@CanIgnoreReturnValue
public Builder
setAnnotations(MonitoringAnnotations annotations) {
if (entries == null) {
throw new IllegalStateException("setAnnotations cannot be called after build");
}
this.annotations = annotations;
return this;
}
public PrimitiveSet
build() throws GeneralSecurityException {
if (entries == null) {
throw new IllegalStateException("build cannot be called twice");
}
// Note that we currently don't enforce that primary must be set.
PrimitiveSet
output =
new PrimitiveSet
(entries, entriesInKeysetOrder, primary, annotations, primitiveClass);
this.entries = null;
return output;
}
private Builder(Class
primitiveClass) {
this.primitiveClass = primitiveClass;
this.annotations = MonitoringAnnotations.EMPTY;
}
}
public static
Builder
newBuilder(Class
primitiveClass) {
return new Builder
(primitiveClass);
}
}