本文属于机器翻译版本。若本译文内容与英语原文存在差异，则一律以英文原文为准。
# 数据密钥缓存示例代码
该代码示例在 Java 和 Python 中创建使用[本地缓存](data-caching-details.md#simplecache)的简易数据密钥缓存实施。该代码创建了两个本地缓存实例：一个用于加密[数据的数据生产](#caching-producer)者，另一个用于解密[数据的数据使用者](#caching-consumer)（AWS Lambda 函数）。有关每种语言的数据密钥缓存实施的详细信息，请参阅适用于 AWS Encryption SDK的 [Javadoc](https://aws.github.io/aws-encryption-sdk-java/) 和 [Python 文档](https://aws-encryption-sdk-python.readthedocs.io/en/latest/)。
数据密钥缓存适用于 AWS Encryption SDK 支持的所有[编程语言](programming-languages.md)。
有关在中使用数据密钥缓存的完整且经过测试的示例 AWS Encryption SDK，请参阅：
+ C/C\$1\$1：[caching\$1cmm.cpp](https://github.com/aws/aws-encryption-sdk-c/blob/master/examples/caching_cmm.cpp)
+ Java：[SimpleDataKeyCachingExample.](https://github.com/aws/aws-encryption-sdk-java/blob/master/src/examples/java/com/amazonaws/crypto/examples/v2/SimpleDataKeyCachingExample.java) java
+ JavaScript 浏览器：[caching\$1cmm.ts](https://github.com/aws/aws-encryption-sdk-javascript/blob/master/modules/example-browser/src/caching_cmm.ts)
+ JavaScript Node.js: [caching\$1cmm.ts](https://github.com/aws/aws-encryption-sdk-javascript/blob/master/modules/example-node/src/caching_cmm.ts)
+ Python：[data\$1key\$1caching\$1basic.py](https://github.com/aws/aws-encryption-sdk-python/blob/master/examples/src/legacy/data_key_caching_basic.py)
## Producer
制作者获取地图，将其转换为 JSON，使用对其进行加密，然后将密文记录推送到每个地图中的 Kinesi [s 流](https://aws.amazon.com/kinesis/streams/)。 AWS Encryption SDK AWS 区域
该代码定义了[缓存加密材料管理器](data-caching-details.md#caching-cmm)（缓存 CMM），并将其与[本地缓存](data-caching-details.md#simplecache)和相关 [AWS KMS 主密钥提供程序](concepts.md#master-key-provider)关联。缓存 CMM 缓存来自主密钥提供程序的数据密钥（和[相关的加密材料](data-caching-details.md#cache-entries)）。它还代表该开发工具包与缓存进行交互，并实施您设置的安全阈值。
由于对加密方法的调用指定缓存 CMM 而非常规[缓存加密材料管理器（CMM）](concepts.md#crypt-materials-manager)或主密钥提供程序，加密将使用数据密钥缓存。
------
#### [ Java ]
以下示例使用版本 2。 *的 x 个* AWS Encryption SDK for Java。版本 3。 *其中 x* AWS Encryption SDK for Java 已弃用数据密钥缓存 CMM。使用版本 3。 *x*，你也可以使用[AWS KMS 分层密钥环](use-hierarchical-keyring.md)，这是一种替代的加密材料缓存解决方案。
```
/*
* Copyright 2017 Amazon.com, Inc. or its affiliates. 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. A copy of the License is located at
*
* http://aws.amazon.com/apache2.0
*
* or in the "license" file accompanying this file. This file 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 com.amazonaws.crypto.examples.kinesisdatakeycaching;
import com.amazonaws.encryptionsdk.AwsCrypto;
import com.amazonaws.encryptionsdk.CommitmentPolicy;
import com.amazonaws.encryptionsdk.CryptoResult;
import com.amazonaws.encryptionsdk.MasterKeyProvider;
import com.amazonaws.encryptionsdk.caching.CachingCryptoMaterialsManager;
import com.amazonaws.encryptionsdk.caching.LocalCryptoMaterialsCache;
import com.amazonaws.encryptionsdk.kmssdkv2.KmsMasterKey;
import com.amazonaws.encryptionsdk.kmssdkv2.KmsMasterKeyProvider;
import com.amazonaws.encryptionsdk.multi.MultipleProviderFactory;
import com.amazonaws.util.json.Jackson;
import java.util.ArrayList;
import java.util.HashMap;
import java.util.List;
import java.util.Map;
import java.util.UUID;
import java.util.concurrent.TimeUnit;
import software.amazon.awssdk.auth.credentials.AwsCredentialsProvider;
import software.amazon.awssdk.auth.credentials.DefaultCredentialsProvider;
import software.amazon.awssdk.core.SdkBytes;
import software.amazon.awssdk.regions.Region;
import software.amazon.awssdk.services.kinesis.KinesisClient;
import software.amazon.awssdk.services.kms.KmsClient;
/**
* Pushes data to Kinesis Streams in multiple Regions.
*/
public class MultiRegionRecordPusher {
private static final long MAX_ENTRY_AGE_MILLISECONDS = 300000;
private static final long MAX_ENTRY_USES = 100;
private static final int MAX_CACHE_ENTRIES = 100;
private final String streamName_;
private final ArrayList kinesisClients_;
private final CachingCryptoMaterialsManager cachingMaterialsManager_;
private final AwsCrypto crypto_;
/**
* Creates an instance of this object with Kinesis clients for all target Regions and a cached
* key provider containing KMS master keys in all target Regions.
*/
public MultiRegionRecordPusher(final Region[] regions, final String kmsAliasName,
final String streamName) {
streamName_ = streamName;
crypto_ = AwsCrypto.builder()
.withCommitmentPolicy(CommitmentPolicy.RequireEncryptRequireDecrypt)
.build();
kinesisClients_ = new ArrayList<>();
AwsCredentialsProvider credentialsProvider = DefaultCredentialsProvider.builder().build();
// Build KmsMasterKey and AmazonKinesisClient objects for each target region
List masterKeys = new ArrayList<>();
for (Region region : regions) {
kinesisClients_.add(KinesisClient.builder()
.credentialsProvider(credentialsProvider)
.region(region)
.build());
KmsMasterKey regionMasterKey = KmsMasterKeyProvider.builder()
.defaultRegion(region)
.builderSupplier(() -> KmsClient.builder().credentialsProvider(credentialsProvider))
.buildStrict(kmsAliasName)
.getMasterKey(kmsAliasName);
masterKeys.add(regionMasterKey);
}
// Collect KmsMasterKey objects into single provider and add cache
MasterKeyProvider masterKeyProvider = MultipleProviderFactory.buildMultiProvider(
KmsMasterKey.class,
masterKeys
);
cachingMaterialsManager_ = CachingCryptoMaterialsManager.newBuilder()
.withMasterKeyProvider(masterKeyProvider)
.withCache(new LocalCryptoMaterialsCache(MAX_CACHE_ENTRIES))
.withMaxAge(MAX_ENTRY_AGE_MILLISECONDS, TimeUnit.MILLISECONDS)
.withMessageUseLimit(MAX_ENTRY_USES)
.build();
}
/**
* JSON serializes and encrypts the received record data and pushes it to all target streams.
*/
public void putRecord(final Map data) {
String partitionKey = UUID.randomUUID().toString();
Map encryptionContext = new HashMap<>();
encryptionContext.put("stream", streamName_);
// JSON serialize data
String jsonData = Jackson.toJsonString(data);
// Encrypt data
CryptoResult result = crypto_.encryptData(
cachingMaterialsManager_,
jsonData.getBytes(),
encryptionContext
);
byte[] encryptedData = result.getResult();
// Put records to Kinesis stream in all Regions
for (KinesisClient regionalKinesisClient : kinesisClients_) {
regionalKinesisClient.putRecord(builder ->
builder.streamName(streamName_)
.data(SdkBytes.fromByteArray(encryptedData))
.partitionKey(partitionKey));
}
}
}
```
------
#### [ Python ]
```
"""
Copyright 2017 Amazon.com, Inc. or its affiliates. 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. A copy of the License is located at
https://aws.amazon.com/apache-2-0/
or in the "license" file accompanying this file. This file 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.
"""
import json
import uuid
from aws_encryption_sdk import EncryptionSDKClient, StrictAwsKmsMasterKeyProvider, CachingCryptoMaterialsManager, LocalCryptoMaterialsCache, CommitmentPolicy
from aws_encryption_sdk.key_providers.kms import KMSMasterKey
import boto3
class MultiRegionRecordPusher(object):
"""Pushes data to Kinesis Streams in multiple Regions."""
CACHE_CAPACITY = 100
MAX_ENTRY_AGE_SECONDS = 300.0
MAX_ENTRY_MESSAGES_ENCRYPTED = 100
def __init__(self, regions, kms_alias_name, stream_name):
self._kinesis_clients = []
self._stream_name = stream_name
# Set up EncryptionSDKClient
_client = EncryptionSDKClient(CommitmentPolicy.REQUIRE_ENCRYPT_REQUIRE_DECRYPT)
# Set up KMSMasterKeyProvider with cache
_key_provider = StrictAwsKmsMasterKeyProvider(kms_alias_name)
# Add MasterKey and Kinesis client for each Region
for region in regions:
self._kinesis_clients.append(boto3.client('kinesis', region_name=region))
regional_master_key = KMSMasterKey(
client=boto3.client('kms', region_name=region),
key_id=kms_alias_name
)
_key_provider.add_master_key_provider(regional_master_key)
cache = LocalCryptoMaterialsCache(capacity=self.CACHE_CAPACITY)
self._materials_manager = CachingCryptoMaterialsManager(
master_key_provider=_key_provider,
cache=cache,
max_age=self.MAX_ENTRY_AGE_SECONDS,
max_messages_encrypted=self.MAX_ENTRY_MESSAGES_ENCRYPTED
)
def put_record(self, record_data):
"""JSON serializes and encrypts the received record data and pushes it to all target streams.
:param dict record_data: Data to write to stream
"""
# Kinesis partition key to randomize write load across stream shards
partition_key = uuid.uuid4().hex
encryption_context = {'stream': self._stream_name}
# JSON serialize data
json_data = json.dumps(record_data)
# Encrypt data
encrypted_data, _header = _client.encrypt(
source=json_data,
materials_manager=self._materials_manager,
encryption_context=encryption_context
)
# Put records to Kinesis stream in all Regions
for client in self._kinesis_clients:
client.put_record(
StreamName=self._stream_name,
Data=encrypted_data,
PartitionKey=partition_key
)
```
------
## 使用者
数据消费端是一个由 [Kinesis](https://aws.amazon.com/kinesis/) 事件触发的 [AWS Lambda](https://aws.amazon.com/lambda/) 函数。其解密并反序列化每个记录，并将明文记录写入到同一区域中的 [Amazon DynamoDB](https://aws.amazon.com/dynamodb/) 表。
与生成器代码一样，消费端代码在对 Decrypt 方法的调用中使用缓存加密材料管理器（缓存 CMM）以启用数据密钥缓存。
Java 代码使用指定的在*严格模式下*构建主密钥提供程序 AWS KMS key。解密时无需使用严格模式，但这是[最佳实践](best-practices.md#strict-discovery-mode)。Python 代码使用*发现模式*，允许 AWS Encryption SDK 使用加密数据密钥的任何包装密钥对其进行解密。
------
#### [ Java ]
以下示例使用版本 2。 *的 x 个* AWS Encryption SDK for Java。版本 3。 *其中 x* AWS Encryption SDK for Java 已弃用数据密钥缓存 CMM。使用版本 3。 *x*，你也可以使用[AWS KMS 分层密钥环](use-hierarchical-keyring.md)，这是一种替代的加密材料缓存解决方案。
此代码创建了在严格模式下解密的主密钥提供程序。 AWS Encryption SDK 只能使用 AWS KMS keys 您指定的来解密您的消息。
```
/*
* Copyright 2017 Amazon.com, Inc. or its affiliates. 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. A copy of the License is located at
*
* http://aws.amazon.com/apache2.0
*
* or in the "license" file accompanying this file. This file 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 com.amazonaws.crypto.examples.kinesisdatakeycaching;
import com.amazonaws.encryptionsdk.AwsCrypto;
import com.amazonaws.encryptionsdk.CommitmentPolicy;
import com.amazonaws.encryptionsdk.CryptoResult;
import com.amazonaws.encryptionsdk.caching.CachingCryptoMaterialsManager;
import com.amazonaws.encryptionsdk.caching.LocalCryptoMaterialsCache;
import com.amazonaws.encryptionsdk.kmssdkv2.KmsMasterKeyProvider;
import com.amazonaws.services.lambda.runtime.Context;
import com.amazonaws.services.lambda.runtime.events.KinesisEvent;
import com.amazonaws.services.lambda.runtime.events.KinesisEvent.KinesisEventRecord;
import com.amazonaws.util.BinaryUtils;
import java.io.UnsupportedEncodingException;
import java.nio.ByteBuffer;
import java.nio.charset.StandardCharsets;
import java.util.concurrent.TimeUnit;
import software.amazon.awssdk.enhanced.dynamodb.DynamoDbEnhancedClient;
import software.amazon.awssdk.enhanced.dynamodb.DynamoDbTable;
import software.amazon.awssdk.enhanced.dynamodb.TableSchema;
/**
* Decrypts all incoming Kinesis records and writes records to DynamoDB.
*/
public class LambdaDecryptAndWrite {
private static final long MAX_ENTRY_AGE_MILLISECONDS = 600000;
private static final int MAX_CACHE_ENTRIES = 100;
private final CachingCryptoMaterialsManager cachingMaterialsManager_;
private final AwsCrypto crypto_;
private final DynamoDbTable- table_;
/**
* Because the cache is used only for decryption, the code doesn't set the max bytes or max
* message security thresholds that are enforced only on on data keys used for encryption.
*/
public LambdaDecryptAndWrite() {
String kmsKeyArn = System.getenv("CMK_ARN");
cachingMaterialsManager_ = CachingCryptoMaterialsManager.newBuilder()
.withMasterKeyProvider(KmsMasterKeyProvider.builder().buildStrict(kmsKeyArn))
.withCache(new LocalCryptoMaterialsCache(MAX_CACHE_ENTRIES))
.withMaxAge(MAX_ENTRY_AGE_MILLISECONDS, TimeUnit.MILLISECONDS)
.build();
crypto_ = AwsCrypto.builder()
.withCommitmentPolicy(CommitmentPolicy.RequireEncryptRequireDecrypt)
.build();
String tableName = System.getenv("TABLE_NAME");
DynamoDbEnhancedClient dynamodb = DynamoDbEnhancedClient.builder().build();
table_ = dynamodb.table(tableName, TableSchema.fromClass(Item.class));
}
/**
* @param event
* @param context
*/
public void handleRequest(KinesisEvent event, Context context)
throws UnsupportedEncodingException {
for (KinesisEventRecord record : event.getRecords()) {
ByteBuffer ciphertextBuffer = record.getKinesis().getData();
byte[] ciphertext = BinaryUtils.copyAllBytesFrom(ciphertextBuffer);
// Decrypt and unpack record
CryptoResult plaintextResult = crypto_.decryptData(cachingMaterialsManager_,
ciphertext);
// Verify the encryption context value
String streamArn = record.getEventSourceARN();
String streamName = streamArn.substring(streamArn.indexOf("/") + 1);
if (!streamName.equals(plaintextResult.getEncryptionContext().get("stream"))) {
throw new IllegalStateException("Wrong Encryption Context!");
}
// Write record to DynamoDB
String jsonItem = new String(plaintextResult.getResult(), StandardCharsets.UTF_8);
System.out.println(jsonItem);
table_.putItem(Item.fromJSON(jsonItem));
}
}
private static class Item {
static Item fromJSON(String jsonText) {
// Parse JSON and create new Item
return new Item();
}
}
}
```
------
#### [ Python ]
此 Python 代码在发现模式下使用主密钥提供程序进行解密。该代码允许 AWS Encryption SDK 使用任何加密数据密钥的包装密钥对其进行解密。[最佳实践](best-practices.md#strict-discovery-mode)是使用严格模式，在这种模式下，您可以指定可用于解密的包装密钥。
```
"""
Copyright 2017 Amazon.com, Inc. or its affiliates. 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. A copy of the License is located at
https://aws.amazon.com/apache-2-0/
or in the "license" file accompanying this file. This file 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.
"""
import base64
import json
import logging
import os
from aws_encryption_sdk import EncryptionSDKClient, DiscoveryAwsKmsMasterKeyProvider, CachingCryptoMaterialsManager, LocalCryptoMaterialsCache, CommitmentPolicy
import boto3
_LOGGER = logging.getLogger(__name__)
_is_setup = False
CACHE_CAPACITY = 100
MAX_ENTRY_AGE_SECONDS = 600.0
def setup():
"""Sets up clients that should persist across Lambda invocations."""
global encryption_sdk_client
encryption_sdk_client = EncryptionSDKClient(CommitmentPolicy.REQUIRE_ENCRYPT_REQUIRE_DECRYPT)
global materials_manager
key_provider = DiscoveryAwsKmsMasterKeyProvider()
cache = LocalCryptoMaterialsCache(capacity=CACHE_CAPACITY)
# Because the cache is used only for decryption, the code doesn't set
# the max bytes or max message security thresholds that are enforced
# only on on data keys used for encryption.
materials_manager = CachingCryptoMaterialsManager(
master_key_provider=key_provider,
cache=cache,
max_age=MAX_ENTRY_AGE_SECONDS
)
global table
table_name = os.environ.get('TABLE_NAME')
table = boto3.resource('dynamodb').Table(table_name)
global _is_setup
_is_setup = True
def lambda_handler(event, context):
"""Decrypts all incoming Kinesis records and writes records to DynamoDB."""
_LOGGER.debug('New event:')
_LOGGER.debug(event)
if not _is_setup:
setup()
with table.batch_writer() as batch:
for record in event.get('Records', []):
# Record data base64-encoded by Kinesis
ciphertext = base64.b64decode(record['kinesis']['data'])
# Decrypt and unpack record
plaintext, header = encryption_sdk_client.decrypt(
source=ciphertext,
materials_manager=materials_manager
)
item = json.loads(plaintext)
# Verify the encryption context value
stream_name = record['eventSourceARN'].split('/', 1)[1]
if stream_name != header.encryption_context['stream']:
raise ValueError('Wrong Encryption Context!')
# Write record to DynamoDB
batch.put_item(Item=item)
```
------