112 lines
4.0 KiB
Java
112 lines
4.0 KiB
Java
/*
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* Copyright (C) 2023 The Android Open Source Project
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*
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* Licensed under the Apache License, Version 2.0 (the "License");
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* you may not use this file except in compliance with the License.
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* You may obtain a copy of the License at
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*
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* http://www.apache.org/licenses/LICENSE-2.0
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*
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* Unless required by applicable law or agreed to in writing, software
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* distributed under the License is distributed on an "AS IS" BASIS,
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* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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* See the License for the specific language governing permissions and
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* limitations under the License.
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*/
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package android.adservices.topics;
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import android.annotation.FlaggedApi;
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import android.annotation.NonNull;
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import com.android.adservices.flags.Flags;
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import java.util.Arrays;
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import java.util.Objects;
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/**
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* Encrypted form of {@link android.adservices.topics.Topic}. This object will be used to return
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* encrypted topic cipher text along with necessary fields required to decrypt it.
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*
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* <p>Decryption of {@link EncryptedTopic#getEncryptedTopic()} should give json string for {@link
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* Topic}. Example of decrypted json string: {@code { "taxonomy_version": 5, "model_version": 2,
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* "topic_id": 10010 }}
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*
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* <p>Decryption of cipher text is expected to happen on the server with the corresponding algorithm
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* and private key for the public key {@link EncryptedTopic#getKeyIdentifier()}}.
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*
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* <p>Detailed steps on decryption can be found on <a
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* href="https://developer.android.com/design-for-safety/privacy-sandbox/guides/topics">Developer
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* Guide</a>.
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*/
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@FlaggedApi(Flags.FLAG_TOPICS_ENCRYPTION_ENABLED)
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public final class EncryptedTopic {
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@NonNull private final byte[] mEncryptedTopic;
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@NonNull private final String mKeyIdentifier;
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@NonNull private final byte[] mEncapsulatedKey;
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/**
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* Creates encrypted version of the {@link Topic} object.
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*
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* @param encryptedTopic byte array cipher text containing encrypted {@link Topic} json string.
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* @param keyIdentifier key used to identify the public key used for encryption.
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* @param encapsulatedKey encapsulated key generated during HPKE setup.
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*/
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public EncryptedTopic(
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@NonNull byte[] encryptedTopic,
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@NonNull String keyIdentifier,
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@NonNull byte[] encapsulatedKey) {
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mEncryptedTopic = Objects.requireNonNull(encryptedTopic);
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mKeyIdentifier = Objects.requireNonNull(keyIdentifier);
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mEncapsulatedKey = Objects.requireNonNull(encapsulatedKey);
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}
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/** Returns encrypted bytes for the JSON version of the {@link Topic} object as cipher text. */
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@NonNull
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public byte[] getEncryptedTopic() {
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return mEncryptedTopic;
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}
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/** Returns key identifier for the used encryption key. */
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@NonNull
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public String getKeyIdentifier() {
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return mKeyIdentifier;
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}
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/** Returns the encapsulated key generated during HPKE setup. */
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@NonNull
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public byte[] getEncapsulatedKey() {
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return mEncapsulatedKey;
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}
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@Override
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public boolean equals(Object object) {
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if (this == object) return true;
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if (!(object instanceof EncryptedTopic)) return false;
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EncryptedTopic encryptedTopic = (EncryptedTopic) object;
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return Arrays.equals(getEncryptedTopic(), encryptedTopic.getEncryptedTopic())
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&& getKeyIdentifier().equals(encryptedTopic.getKeyIdentifier())
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&& Arrays.equals(getEncapsulatedKey(), encryptedTopic.getEncapsulatedKey());
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}
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@Override
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public int hashCode() {
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return Objects.hash(
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Arrays.hashCode(getEncryptedTopic()),
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getKeyIdentifier(),
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Arrays.hashCode(getEncapsulatedKey()));
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}
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@Override
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public java.lang.String toString() {
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return "EncryptedTopic{"
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+ "mEncryptedTopic="
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+ Arrays.toString(mEncryptedTopic)
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+ ", mKeyIdentifier="
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+ mKeyIdentifier
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+ ", mEncapsulatedKey="
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+ Arrays.toString(mEncapsulatedKey)
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+ '}';
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}
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}
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