Add Cloud KMS based secret storage

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Created by MOE: https://github.com/google/moe
MOE_MIGRATED_REVID=147791972

java/google/registry/model/server/KmsSecretRevision.java

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+// Copyright 2017 The Nomulus Authors. 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.
+// 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 google.registry.model.server;
+
+import static com.google.common.base.Preconditions.checkArgument;
+import static google.registry.model.common.EntityGroupRoot.getCrossTldKey;
+import static google.registry.model.ofy.Ofy.RECOMMENDED_MEMCACHE_EXPIRATION;
+
+import com.googlecode.objectify.Key;
+import com.googlecode.objectify.annotation.Cache;
+import com.googlecode.objectify.annotation.Entity;
+import com.googlecode.objectify.annotation.Id;
+import com.googlecode.objectify.annotation.Parent;
+import google.registry.model.Buildable;
+import google.registry.model.CreateAutoTimestamp;
+import google.registry.model.ImmutableObject;
+import google.registry.model.annotations.ReportedOn;
+
+/**
+ * An encrypted value.
+ *
+ * <p>Used to store passwords and other sensitive information in Datastore. Multiple versions of a
+ * {@link KmsSecretRevision} may be persisted but only the latest version is primary. A key to the
+ * primary version is stored by {@link KmsSecret#latestRevision}.
+ *
+ * <p>The value can be encrypted and decrypted using Cloud KMS.
+ *
+ * @see <a href="https://cloud.google.com/kms/docs/">Google Cloud Key Management Service
+ *     Documentation</a>
+ * @see google.registry.keyring.kms.KmsKeyring
+ */
+@Entity
+@ReportedOn
+@Cache(expirationSeconds = RECOMMENDED_MEMCACHE_EXPIRATION)
+public class KmsSecretRevision extends ImmutableObject {
+
+  /**
+   * The maximum allowable secret size. Although Datastore allows entities up to 1 MB in size,
+   * BigQuery imports of Datastore backups limit individual columns (entity attributes) to 64 KB.
+   */
+  private static final int MAX_SECRET_SIZE_BYTES = 64 * 1024 * 1024;
+
+  /** The revision of this secret. */
+  @Id long revisionKey;
+
+  /** The parent {@link KmsSecret} which contains metadata about this {@link KmsSecretRevision}. */
+  @Parent Key<KmsSecret> parent;
+
+  /**
+   * The name of the {@code cryptoKeyVersion} associated with this {@link KmsSecretRevision}.
+   *
+   * @see <a
+   *     href="https://cloud.google.com/kms/docs/reference/rest/v1beta1/projects.locations.keyRings.cryptoKeys.cryptoKeyVersions">projects.locations.keyRings.cryptoKeys.cryptoKeyVersions</a>
+   */
+  String kmsCryptoKeyVersionName;
+
+  /**
+   * The base64-encoded encrypted value of this {@link KmsSecretRevision} as returned by the Cloud
+   * KMS API.
+   *
+   * @see <a
+   *     href="https://cloud.google.com/kms/docs/reference/rest/v1beta1/projects.locations.keyRings.cryptoKeys/encrypt">projects.locations.keyRings.cryptoKeys.encrypt</a>
+   */
+  String encryptedValue;
+
+  /** An automatically managed creation timestamp. */
+  CreateAutoTimestamp creationTime = CreateAutoTimestamp.create(null);
+
+  public String getKmsCryptoKeyVersionName() {
+    return kmsCryptoKeyVersionName;
+  }
+
+  public String getEncryptedValue() {
+    return encryptedValue;
+  }
+
+  /** A builder for constructing {@link KmsSecretRevision} entities, since they are immutable. */
+  public static class Builder extends Buildable.Builder<KmsSecretRevision> {
+
+    public Builder setKmsCryptoKeyVersionName(String kmsCryptoKeyVersionName) {
+      getInstance().kmsCryptoKeyVersionName = kmsCryptoKeyVersionName;
+      return this;
+    }
+
+    public Builder setEncryptedValue(String encryptedValue) {
+      checkArgument(
+          encryptedValue.length() <= MAX_SECRET_SIZE_BYTES,
+          "Secret is greater than %s bytes",
+          MAX_SECRET_SIZE_BYTES);
+
+      getInstance().encryptedValue = encryptedValue;
+      return this;
+    }
+
+    /**
+     * Set the parent {@link KmsSecret}.
+     *
+     * <p>The secret may not exist yet, so it is referred to by name rather than by reference.
+     */
+    public Builder setParent(String secretName) {
+      getInstance().parent = Key.create(getCrossTldKey(), KmsSecret.class, secretName);
+      return this;
+    }
+  }
+}