All Products
Search
Document Center

Object Storage Service:Server-side encryption

Last Updated:Oct 18, 2023

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.

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 Initialization.

  • 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.

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.

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 specifying an encryption method are encrypted by using the default encryption method.

using Aliyun.OSS;
using Aliyun.OSS.Common;
// 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. 
var endpoint = "yourEndpoint";
// 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. 
var accessKeyId = Environment.GetEnvironmentVariable("OSS_ACCESS_KEY_ID");
var accessKeySecret = Environment.GetEnvironmentVariable("OSS_ACCESS_KEY_SECRET");
// Specify the name of the bucket. Example: examplebucket. 
var bucketName = "examplebucket";
// Create an OSSClient instance. 
var client = new OssClient(endpoint, accessKeyId, accessKeySecret);
try
{
    // Configure server-side encryption for the bucket. 
    var request = new SetBucketEncryptionRequest(bucketName, "KMS", null);
    client.SetBucketEncryption(request);
    Console.WriteLine("Set bucket:{0} Encryption succeeded ", bucketName);
}
catch (OssException ex)
{
    Console.WriteLine("Failed with error code: {0}; Error info: {1}. \nRequestID:{2}\tHostID:{3}",
        ex.ErrorCode, ex.Message, ex.RequestId, ex.HostId);
}
catch (Exception ex)
{
    Console.WriteLine("Failed with error info: {0}", ex.Message);
}

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:

using Aliyun.OSS;
using Aliyun.OSS.Common;
// 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. 
var endpoint = "yourEndpoint";
// 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. 
var accessKeyId = Environment.GetEnvironmentVariable("OSS_ACCESS_KEY_ID");
var accessKeySecret = Environment.GetEnvironmentVariable("OSS_ACCESS_KEY_SECRET");
// Specify the name of the bucket. Example: examplebucket. 
var bucketName = "examplebucket";
// Create an OSSClient instance. 
var client = new OssClient(endpoint, accessKeyId, accessKeySecret);
try
{
    // Query the server-side encryption configurations of the bucket. 
    var result = client.GetBucketEncryption(bucketName);
    Console.WriteLine("Get bucket:{0} Encryption succeeded ", bucketName);

    Console.WriteLine("SSEAlgorithm: {0}", result.SSEAlgorithm);
    Console.WriteLine("KMSMasterKeyID: {0}", result.KMSMasterKeyID);

}
catch (OssException ex)
{
    Console.WriteLine("Failed with error code: {0}; Error info: {1}. \nRequestID:{2}\tHostID:{3}",
        ex.ErrorCode, ex.Message, ex.RequestId, ex.HostId);
}
catch (Exception ex)
{
    Console.WriteLine("Failed with error info: {0}", ex.Message);
}

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:

using Aliyun.OSS;
using Aliyun.OSS.Common;
// 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. 
var endpoint = "yourEndpoint";
// 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. 
var accessKeyId = Environment.GetEnvironmentVariable("OSS_ACCESS_KEY_ID");
var accessKeySecret = Environment.GetEnvironmentVariable("OSS_ACCESS_KEY_SECRET");
// Specify the name of the bucket. Example: examplebucket. 
var bucketName = "examplebucket";
// Create an OSSClient instance. 
var client = new OssClient(endpoint, accessKeyId, accessKeySecret);
try
{
    // Delete the server-side encryption configurations of the bucket. 
    client.DeleteBucketEncryption(bucketName);
    Console.WriteLine("Delete bucket:{0} Encryption succeeded ", bucketName);
}
catch (OssException ex)
{
    Console.WriteLine("Failed with error code: {0}; Error info: {1}. \nRequestID:{2}\tHostID:{3}",
        ex.ErrorCode, ex.Message, ex.RequestId, ex.HostId);
}
catch (Exception ex)
{
    Console.WriteLine("Failed with error info: {0}", ex.Message);
}

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.