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代码示例
C#
如需了解如何安装和使用 Cloud KMS 客户端库,请参阅 Cloud KMS 客户端库。
如需向 Cloud KMS 进行身份验证,请设置应用默认凭据。 如需了解详情,请参阅为本地开发环境设置身份验证。
using Google.Cloud.Kms.V1;
using Google.Protobuf;
using System.Text;
public class DecryptSymmetricSample
{
public string DecryptSymmetric(
string projectId = "my-project", string locationId = "us-east1", string keyRingId = "my-key-ring", string keyId = "my-key",
byte[] ciphertext = null)
{
// Create the client.
KeyManagementServiceClient client = KeyManagementServiceClient.Create();
// Build the key name.
CryptoKeyName keyName = new CryptoKeyName(projectId, locationId, keyRingId, keyId);
// Call the API.
DecryptResponse result = client.Decrypt(keyName, ByteString.CopyFrom(ciphertext));
// Get the plaintext. Cryptographic plaintexts and ciphertexts are
// always byte arrays.
byte[] plaintext = result.Plaintext.ToByteArray();
// Return the result.
return Encoding.UTF8.GetString(plaintext);
}
}
Go
如需了解如何安装和使用 Cloud KMS 客户端库,请参阅 Cloud KMS 客户端库。
如需向 Cloud KMS 进行身份验证,请设置应用默认凭据。 如需了解详情,请参阅为本地开发环境设置身份验证。
import (
"context"
"fmt"
"hash/crc32"
"io"
kms "cloud.google.com/go/kms/apiv1"
"cloud.google.com/go/kms/apiv1/kmspb"
"google.golang.org/protobuf/types/known/wrapperspb"
)
// decryptSymmetric will decrypt the input ciphertext bytes using the specified symmetric key.
func decryptSymmetric(w io.Writer, name string, ciphertext []byte) error {
// name := "projects/my-project/locations/us-east1/keyRings/my-key-ring/cryptoKeys/my-key"
// ciphertext := []byte("...") // result of a symmetric encryption call
// Create the client.
ctx := context.Background()
client, err := kms.NewKeyManagementClient(ctx)
if err != nil {
return fmt.Errorf("failed to create kms client: %w", err)
}
defer client.Close()
// Optional, but recommended: Compute ciphertext's CRC32C.
crc32c := func(data []byte) uint32 {
t := crc32.MakeTable(crc32.Castagnoli)
return crc32.Checksum(data, t)
}
ciphertextCRC32C := crc32c(ciphertext)
// Build the request.
req := &kmspb.DecryptRequest{
Name: name,
Ciphertext: ciphertext,
CiphertextCrc32C: wrapperspb.Int64(int64(ciphertextCRC32C)),
}
// Call the API.
result, err := client.Decrypt(ctx, req)
if err != nil {
return fmt.Errorf("failed to decrypt ciphertext: %w", err)
}
// Optional, but recommended: perform integrity verification on result.
// For more details on ensuring E2E in-transit integrity to and from Cloud KMS visit:
// https://cloud.google.com/kms/docs/data-integrity-guidelines
if int64(crc32c(result.Plaintext)) != result.PlaintextCrc32C.Value {
return fmt.Errorf("Decrypt: response corrupted in-transit")
}
fmt.Fprintf(w, "Decrypted plaintext: %s", result.Plaintext)
return nil
}
Java
如需了解如何安装和使用 Cloud KMS 客户端库,请参阅 Cloud KMS 客户端库。
如需向 Cloud KMS 进行身份验证,请设置应用默认凭据。 如需了解详情,请参阅为本地开发环境设置身份验证。
import com.google.cloud.kms.v1.CryptoKeyName;
import com.google.cloud.kms.v1.DecryptResponse;
import com.google.cloud.kms.v1.KeyManagementServiceClient;
import com.google.protobuf.ByteString;
import java.io.IOException;
public class DecryptSymmetric {
public void decryptSymmetric() throws IOException {
// TODO(developer): Replace these variables before running the sample.
String projectId = "your-project-id";
String locationId = "us-east1";
String keyRingId = "my-key-ring";
String keyId = "my-key";
byte[] ciphertext = null;
decryptSymmetric(projectId, locationId, keyRingId, keyId, ciphertext);
}
// Decrypt data that was encrypted using a symmetric key.
public void decryptSymmetric(
String projectId, String locationId, String keyRingId, String keyId, byte[] ciphertext)
throws IOException {
// Initialize client that will be used to send requests. This client only
// needs to be created once, and can be reused for multiple requests. After
// completing all of your requests, call the "close" method on the client to
// safely clean up any remaining background resources.
try (KeyManagementServiceClient client = KeyManagementServiceClient.create()) {
// Build the key version name from the project, location, key ring, and
// key.
CryptoKeyName keyName = CryptoKeyName.of(projectId, locationId, keyRingId, keyId);
// Decrypt the response.
DecryptResponse response = client.decrypt(keyName, ByteString.copyFrom(ciphertext));
System.out.printf("Plaintext: %s%n", response.getPlaintext().toStringUtf8());
}
}
}
Node.js
如需了解如何安装和使用 Cloud KMS 客户端库,请参阅 Cloud KMS 客户端库。
如需向 Cloud KMS 进行身份验证,请设置应用默认凭据。 如需了解详情,请参阅为本地开发环境设置身份验证。
//
// TODO(developer): Uncomment these variables before running the sample.
//
// const projectId = 'my-project';
// const locationId = 'us-east1';
// const keyRingId = 'my-key-ring';
// const keyId = 'my-key';
// Ciphertext must be either a Buffer object or a base-64 encoded string
// const ciphertext = Buffer.from('...');
// Imports the Cloud KMS library
const {KeyManagementServiceClient} = require('@google-cloud/kms');
// Instantiates a client
const client = new KeyManagementServiceClient();
// Build the key name
const keyName = client.cryptoKeyPath(projectId, locationId, keyRingId, keyId);
// Optional, but recommended: compute ciphertext's CRC32C.
const crc32c = require('fast-crc32c');
const ciphertextCrc32c = crc32c.calculate(ciphertext);
async function decryptSymmetric() {
const [decryptResponse] = await client.decrypt({
name: keyName,
ciphertext: ciphertext,
ciphertextCrc32c: {
value: ciphertextCrc32c,
},
});
// Optional, but recommended: perform integrity verification on decryptResponse.
// For more details on ensuring E2E in-transit integrity to and from Cloud KMS visit:
// https://cloud.google.com/kms/docs/data-integrity-guidelines
if (
crc32c.calculate(decryptResponse.plaintext) !==
Number(decryptResponse.plaintextCrc32c.value)
) {
throw new Error('Decrypt: response corrupted in-transit');
}
const plaintext = decryptResponse.plaintext.toString();
console.log(`Plaintext: ${plaintext}`);
return plaintext;
}
return decryptSymmetric();
PHP
如需了解如何安装和使用 Cloud KMS 客户端库,请参阅 Cloud KMS 客户端库。
如需向 Cloud KMS 进行身份验证,请设置应用默认凭据。 如需了解详情,请参阅为本地开发环境设置身份验证。
use Google\Cloud\Kms\V1\Client\KeyManagementServiceClient;
use Google\Cloud\Kms\V1\DecryptRequest;
function decrypt_symmetric(
string $projectId = 'my-project',
string $locationId = 'us-east1',
string $keyRingId = 'my-key-ring',
string $keyId = 'my-key',
string $ciphertext = '...'
) {
// Create the Cloud KMS client.
$client = new KeyManagementServiceClient();
// Build the key name.
$keyName = $client->cryptoKeyName($projectId, $locationId, $keyRingId, $keyId);
// Call the API.
$decryptRequest = (new DecryptRequest())
->setName($keyName)
->setCiphertext($ciphertext);
$decryptResponse = $client->decrypt($decryptRequest);
printf('Plaintext: %s' . PHP_EOL, $decryptResponse->getPlaintext());
return $decryptResponse;
}
Python
如需了解如何安装和使用 Cloud KMS 客户端库,请参阅 Cloud KMS 客户端库。
如需向 Cloud KMS 进行身份验证,请设置应用默认凭据。 如需了解详情,请参阅为本地开发环境设置身份验证。
from google.cloud import kms
def decrypt_symmetric(
project_id: str, location_id: str, key_ring_id: str, key_id: str, ciphertext: bytes
) -> kms.DecryptResponse:
"""
Decrypt the ciphertext using the symmetric key
Args:
project_id (string): Google Cloud project ID (e.g. 'my-project').
location_id (string): Cloud KMS location (e.g. 'us-east1').
key_ring_id (string): ID of the Cloud KMS key ring (e.g. 'my-key-ring').
key_id (string): ID of the key to use (e.g. 'my-key').
ciphertext (bytes): Encrypted bytes to decrypt.
Returns:
DecryptResponse: Response including plaintext.
"""
# Create the client.
client = kms.KeyManagementServiceClient()
# Build the key name.
key_name = client.crypto_key_path(project_id, location_id, key_ring_id, key_id)
# Optional, but recommended: compute ciphertext's CRC32C.
# See crc32c() function defined below.
ciphertext_crc32c = crc32c(ciphertext)
# Call the API.
decrypt_response = client.decrypt(
request={
"name": key_name,
"ciphertext": ciphertext,
"ciphertext_crc32c": ciphertext_crc32c,
}
)
# Optional, but recommended: perform integrity verification on decrypt_response.
# For more details on ensuring E2E in-transit integrity to and from Cloud KMS visit:
# https://cloud.google.com/kms/docs/data-integrity-guidelines
if not decrypt_response.plaintext_crc32c == crc32c(decrypt_response.plaintext):
raise Exception(
"The response received from the server was corrupted in-transit."
)
# End integrity verification
print(f"Plaintext: {decrypt_response.plaintext!r}")
return decrypt_response
def crc32c(data: bytes) -> int:
"""
Calculates the CRC32C checksum of the provided data.
Args:
data: the bytes over which the checksum should be calculated.
Returns:
An int representing the CRC32C checksum of the provided bytes.
"""
import crcmod # type: ignore
crc32c_fun = crcmod.predefined.mkPredefinedCrcFun("crc-32c")
return crc32c_fun(data)
Ruby
如需了解如何安装和使用 Cloud KMS 客户端库,请参阅 Cloud KMS 客户端库。
如需向 Cloud KMS 进行身份验证,请设置应用默认凭据。 如需了解详情,请参阅为本地开发环境设置身份验证。
# TODO(developer): uncomment these values before running the sample.
# project_id = "my-project"
# location_id = "us-east1"
# key_ring_id = "my-key-ring"
# key_id = "my-key"
# ciphertext = "..."
# Require the library.
require "google/cloud/kms"
# Create the client.
client = Google::Cloud::Kms.key_management_service
# Build the parent key name.
key_name = client.crypto_key_path project: project_id,
location: location_id,
key_ring: key_ring_id,
crypto_key: key_id
# Call the API.
response = client.decrypt name: key_name, ciphertext: ciphertext
puts "Plaintext: #{response.plaintext}"
后续步骤
如需搜索和过滤其他 Google Cloud 产品的代码示例,请参阅 Google Cloud 示例浏览器。