verify_asymmetric_ec.php

<?php
/*
 * Copyright 2020 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.
 */

declare(strict_types=1);

namespace Google\Cloud\Samples\Kms;

// [START kms_verify_asymmetric_signature_ec]
use Google\Cloud\Kms\V1\Client\KeyManagementServiceClient;
use Google\Cloud\Kms\V1\GetPublicKeyRequest;

function verify_asymmetric_ec(
    string $projectId = 'my-project',
    string $locationId = 'us-east1',
    string $keyRingId = 'my-key-ring',
    string $keyId = 'my-key',
    string $versionId = '123',
    string $message = '...',
    string $signature = '...'
): bool {
    // Create the Cloud KMS client.
    $client = new KeyManagementServiceClient();

    // Build the key version name.
    $keyVersionName = $client->cryptoKeyVersionName($projectId, $locationId, $keyRingId, $keyId, $versionId);

    // Get the public key.
    $getPublicKeyRequest = (new GetPublicKeyRequest())
        ->setName($keyVersionName);
    $publicKey = $client->getPublicKey($getPublicKeyRequest);

    // Verify the signature. The hash algorithm must correspond to the key
    // algorithm. The openssl_verify command returns 1 on success, 0 on falure.
    $verified = openssl_verify($message, $signature, $publicKey->getPem(), OPENSSL_ALGO_SHA256) === 1;
    printf('Signature verified: %s', $verified);

    return $verified;
}
// [END kms_verify_asymmetric_signature_ec]

// The following 2 lines are only needed to run the samples
require_once __DIR__ . '/../../testing/sample_helpers.php';
return \Google\Cloud\Samples\execute_sample(__FILE__, __NAMESPACE__, $argv);