透過對稱金鑰加密及解密資料

本頁面說明如何使用 Cloud Key Management Service (Cloud KMS) 執行下列對稱金鑰作業:

  • 使用 Cloud KMS 金鑰加密文字或二進位檔內容 (明文)。
  • 解密使用 Cloud KMS 金鑰加密的密文。

如要使用非對稱金鑰加密,請參閱「透過非對稱金鑰加密及解密資料」。如要瞭解原始對稱式加密,請參閱原始對稱式加密

事前準備

  1. 建立金鑰環建立金鑰

  2. 確保呼叫加密與解密方法的使用者具備金鑰的 cloudkms.cryptoKeyVersions.useToEncryptcloudkms.cryptoKeyVersions.useToDecrypt 權限。

    允許使用者加密或解密的其中一種方法是,將使用者新增至該金鑰的 roles/cloudkms.cryptoKeyEncrypterroles/cloudkms.cryptoKeyDecrypterroles/cloudkms.cryptoKeyEncrypterDecrypter 身分與存取權管理角色。roles/cloudkms.admin 角色提供這兩項權限。詳情請參閱「權限與角色」。

加密

gcloud

如要在指令列上使用 Cloud KMS,請先安裝或升級至最新版 Google Cloud CLI

gcloud kms encrypt \
    --key KEY_NAME \
    --keyring KEY_RING \
    --location LOCATION  \
    --plaintext-file FILE_TO_ENCRYPT \
    --ciphertext-file ENCRYPTED_OUTPUT

更改下列內容:

  • KEY_NAME:要用於加密的金鑰名稱。
  • KEY_RING:金鑰所屬金鑰環的名稱。
  • LOCATION:包含金鑰環的 Cloud KMS 位置。
  • FILE_TO_ENCRYPT:要加密的檔案路徑。
  • ENCRYPTED_OUTPUT:您要儲存加密輸出內容的路徑。

如要瞭解所有旗標和可能的值,請執行含有 --help 旗標的指令。

C#

如要執行這段程式碼,請先設定 C# 開發環境,然後安裝 Cloud KMS C# SDK


using Google.Cloud.Kms.V1;
using Google.Protobuf;
using System.Text;

public class EncryptSymmetricSample
{
    public byte[] EncryptSymmetric(
      string projectId = "my-project", string locationId = "us-east1", string keyRingId = "my-key-ring", string keyId = "my-key",
      string message = "Sample message")
    {
        // Create the client.
        KeyManagementServiceClient client = KeyManagementServiceClient.Create();

        // Build the key name.
        CryptoKeyName keyName = new CryptoKeyName(projectId, locationId, keyRingId, keyId);

        // Convert the message into bytes. Cryptographic plaintexts and
        // ciphertexts are always byte arrays.
        byte[] plaintext = Encoding.UTF8.GetBytes(message);

        // Call the API.
        EncryptResponse result = client.Encrypt(keyName, ByteString.CopyFrom(plaintext));

        // Return the ciphertext.
        return result.Ciphertext.ToByteArray();
    }
}

Go

如要執行這段程式碼,請先設定 Go 開發環境,並安裝 Cloud KMS Go SDK

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"
)

// encryptSymmetric encrypts the input plaintext with the specified symmetric
// Cloud KMS key.
func encryptSymmetric(w io.Writer, name string, message string) error {
	// name := "projects/my-project/locations/us-east1/keyRings/my-key-ring/cryptoKeys/my-key"
	// message := "Sample message"

	// 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()

	// Convert the message into bytes. Cryptographic plaintexts and
	// ciphertexts are always byte arrays.
	plaintext := []byte(message)

	// Optional but recommended: Compute plaintext's CRC32C.
	crc32c := func(data []byte) uint32 {
		t := crc32.MakeTable(crc32.Castagnoli)
		return crc32.Checksum(data, t)
	}
	plaintextCRC32C := crc32c(plaintext)

	// Build the request.
	req := &kmspb.EncryptRequest{
		Name:            name,
		Plaintext:       plaintext,
		PlaintextCrc32C: wrapperspb.Int64(int64(plaintextCRC32C)),
	}

	// Call the API.
	result, err := client.Encrypt(ctx, req)
	if err != nil {
		return fmt.Errorf("failed to encrypt: %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 result.VerifiedPlaintextCrc32C == false {
		return fmt.Errorf("Encrypt: request corrupted in-transit")
	}
	if int64(crc32c(result.Ciphertext)) != result.CiphertextCrc32C.Value {
		return fmt.Errorf("Encrypt: response corrupted in-transit")
	}

	fmt.Fprintf(w, "Encrypted ciphertext: %s", result.Ciphertext)
	return nil
}

Java

如要執行這段程式碼,請先設定 Java 開發環境,然後安裝 Cloud KMS Java SDK

import com.google.cloud.kms.v1.CryptoKeyName;
import com.google.cloud.kms.v1.EncryptResponse;
import com.google.cloud.kms.v1.KeyManagementServiceClient;
import com.google.protobuf.ByteString;
import java.io.IOException;

public class EncryptSymmetric {

  public void encryptSymmetric() 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";
    String plaintext = "Plaintext to encrypt";
    encryptSymmetric(projectId, locationId, keyRingId, keyId, plaintext);
  }

  // Encrypt data with a given key.
  public void encryptSymmetric(
      String projectId, String locationId, String keyRingId, String keyId, String plaintext)
      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, key,
      // and key version.
      CryptoKeyName keyVersionName = CryptoKeyName.of(projectId, locationId, keyRingId, keyId);

      // Encrypt the plaintext.
      EncryptResponse response = client.encrypt(keyVersionName, ByteString.copyFromUtf8(plaintext));
      System.out.printf("Ciphertext: %s%n", response.getCiphertext().toStringUtf8());
    }
  }
}

Node.js

如要執行這段程式碼,請先設定 Node.js 開發環境,並安裝 Cloud KMS Node.js SDK

//
// 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';
// const plaintextBuffer = 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 plaintext's CRC32C.
const crc32c = require('fast-crc32c');
const plaintextCrc32c = crc32c.calculate(plaintextBuffer);

async function encryptSymmetric() {
  const [encryptResponse] = await client.encrypt({
    name: keyName,
    plaintext: plaintextBuffer,
    plaintextCrc32c: {
      value: plaintextCrc32c,
    },
  });

  const ciphertext = encryptResponse.ciphertext;

  // Optional, but recommended: perform integrity verification on encryptResponse.
  // 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 (!encryptResponse.verifiedPlaintextCrc32c) {
    throw new Error('Encrypt: request corrupted in-transit');
  }
  if (
    crc32c.calculate(ciphertext) !==
    Number(encryptResponse.