Server-side encryption - Object Storage Service - Alibaba Cloud Documentation Center

Object Storage Service (OSS) can encrypt uploaded data on the server. This is called server-side encryption. When you upload data to OSS, OSS encrypts the data and stores the encrypted data. When you download data from OSS, OSS decrypts the data and returns the decrypted data. In addition, a header is added to the response to declare that the data is encrypted on the server.

Background information

OSS provides the following server-side encryption methods:

Server-side encryption that uses KMS-managed CMKs (SSE-KMS)
When you upload an object, you can use the CMK with a specified ID or the default CMK managed by KMS to encrypt data. This method is cost-effective because you do not need to send data to the KMS server for encryption and decryption.
Important
You are charged when you call API operations to encrypt or decrypt data by using KMS keys.
Server-side encryption that uses OSS-managed keys (SSE-OSS)
When you upload an object, OSS encrypts the object on the server side by using AES-256 keys managed by OSS. OSS server-side encryption uses AES-256 to encrypt objects by using different data keys. AES-256 uses master keys that are regularly rotated to encrypt data keys.

Important

Only one server-side encryption method can be used for an object at a time.
If you enable server-side encryption for a bucket, you can still configure a separate encryption method for objects that you upload or copy to the bucket. The encryption method configured for objects takes precedence. For more information, see PutObject.
For more information about server-side encryption, see Server-side encryption.

Usage notes

In this topic, the public endpoint of the China (Hangzhou) region is used. If you want to access OSS by using other Alibaba Cloud services in the same region as OSS, use an internal endpoint. For more information about the regions and endpoints supported by OSS, see Regions and endpoints.
In this topic, an OSSClient instance is created by using an OSS endpoint. If you want to create an OSSClient instance by using custom domain names or Security Token Service (STS), see Create an OSSClient instance.
To enable encryption for a bucket, you must have the oss:PutBucketEncryption permission. To query the encryption configurations of a bucket, you must have the oss:GetBucketEncryption permission. To delete encryption configurations of a bucket, you must have the oss:DeleteBucketEncryption permission. For more information, see Common examples of RAM policies.

Configure server-side encryption for a bucket

The following sample code provides an example on how to configure a default encryption method for a bucket. After the method is configured, all objects that are uploaded to the bucket without an encryption method are encrypted by using the default encryption method.

#include <alibabacloud/oss/OssClient.h>
using namespace AlibabaCloud::OSS;

int main(void)
{
    /* Initialize information about the account that is used to access OSS. */
            
    /* Specify the endpoint of the region in which the bucket is located. For example, if the bucket is located in the China (Hangzhou) region, set the endpoint to https://oss-cn-hangzhou.aliyuncs.com. */
    std::string Endpoint = "https://oss-cn-hangzhou.aliyuncs.com";
    /* Specify the name of the bucket. Example: examplebucket. */
    std::string BucketName = "examplebucket";

    /* Initialize resources, such as network resources. */
    InitializeSdk();

    ClientConfiguration conf;
    /* Obtain access credentials from environment variables. Before you run the sample code, make sure that the OSS_ACCESS_KEY_ID and OSS_ACCESS_KEY_SECRET environment variables are configured. */
    auto credentialsProvider = std::make_shared<EnvironmentVariableCredentialsProvider>();
    OssClient client(Endpoint, credentialsProvider, conf);

    SetBucketEncryptionRequest setrequest(BucketName);
    setrequest.setSSEAlgorithm(SSEAlgorithm::KMS);
    /* Configure server-side encryption based on KMS. */
    auto outcome = client.SetBucketEncryption(setrequest);

    if (!outcome.isSuccess()) {
        /* Handle exceptions. */
        std::cout << "SetBucketEncryption fail" <<
        ",code:" << outcome.error().Code() <<
        ",message:" << outcome.error().Message() <<
        ",requestId:" << outcome.error().RequestId() << std::endl;
        return -1;
    }

    /* Release resources, such as network resources. */
    ShutdownSdk();
    return 0;
}

Query the server-side encryption configurations of a bucket

The following sample code provides an example on how to query the server-side encryption configurations of a bucket:

#include <alibabacloud/oss/OssClient.h>
using namespace AlibabaCloud::OSS;

int main(void)
{
    /* Initialize information about the account that is used to access OSS. */
            
    /* Specify the endpoint of the region in which the bucket is located. For example, if the bucket is located in the China (Hangzhou) region, set the endpoint to https://oss-cn-hangzhou.aliyuncs.com. */
    std::string Endpoint = "https://oss-cn-hangzhou.aliyuncs.com";
    /* Specify the name of the bucket. Example: examplebucket. */
    std::string BucketName = "examplebucket";

    /* Initialize resources, such as network resources. */
    InitializeSdk();

    ClientConfiguration conf;
    /* Obtain access credentials from environment variables. Before you run the sample code, make sure that the OSS_ACCESS_KEY_ID and OSS_ACCESS_KEY_SECRET environment variables are configured. */
    auto credentialsProvider = std::make_shared<EnvironmentVariableCredentialsProvider>();
    OssClient client(Endpoint, credentialsProvider, conf);

    /* Query the server-side encryption configurations of the bucket. */   
    GetBucketEncryptionRequest request(BucketName);   
    auto outcome = client.GetBucketEncryption(request);

    if (!outcome.isSuccess()) {
        /* Handle exceptions. */
        std::cout << "GetBucketEncryption fail" <<
        ",code:" << outcome.error().Code() <<
        ",message:" << outcome.error().Message() <<
        ",requestId:" << outcome.error().RequestId() << std::endl;
        return -1;
    }

    /* Release resources, such as network resources. */
    ShutdownSdk();
    return 0;
}

Delete the server-side encryption configurations of a bucket

The following sample code provides an example on how to delete the server-side encryption configurations of a bucket:

#include <alibabacloud/oss/OssClient.h>
using namespace AlibabaCloud::OSS;

int main(void)
{
    /* Initialize information about the account that is used to access OSS. */
            
    /* Specify the endpoint of the region in which the bucket is located. For example, if the bucket is located in the China (Hangzhou) region, set the endpoint to https://oss-cn-hangzhou.aliyuncs.com. */
    std::string Endpoint = "https://oss-cn-hangzhou.aliyuncs.com";
    /* Specify the name of the bucket. Example: examplebucket. */
    std::string BucketName = "examplebucket";

    /* Initialize resources, such as network resources. */
    InitializeSdk();

    ClientConfiguration conf;
    /* Obtain access credentials from environment variables. Before you run the sample code, make sure that the OSS_ACCESS_KEY_ID and OSS_ACCESS_KEY_SECRET environment variables are configured. */
    auto credentialsProvider = std::make_shared<EnvironmentVariableCredentialsProvider>();
    OssClient client(Endpoint, credentialsProvider, conf);

    /* Delete the server-side encryption configurations of the bucket. */   
    DeleteBucketEncryptionRequest request(BucketName);   
    auto outcome = client.DeleteBucketEncryption(request);

    if (!outcome.isSuccess()) {
        /* Handle exceptions. */
        std::cout << "DeleteBucketEncryption fail" <<
        ",code:" << outcome.error().Code() <<
        ",message:" << outcome.error().Message() <<
        ",requestId:" << outcome.error().RequestId() << std::endl;
        return -1;
    }

    /* Release resources, such as network resources. */
    ShutdownSdk();
    return 0;
}

References

For more information about the API operation that you can call to configure server-side encryption, see PutBucketEncryption.
For more information about the API operation that you can call to query server-side encryption configurations, see GetBucketEncryption.
For more information about the API operation that you can call to delete server-side encryption configurations, see DeleteBucketEncryption.