Specifying server-side encryption with Amazon S3 managed keys (SSE-S3) - Amazon Simple Storage Service
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Specifying server-side encryption with Amazon S3 managed keys (SSE-S3)

Important

Amazon S3 now applies server-side encryption with Amazon S3 managed keys (SSE-S3) as the base level of encryption for every bucket in Amazon S3. Starting January 5, 2023, all new object uploads to Amazon S3 are automatically encrypted at no additional cost and with no impact on performance. The automatic encryption status for S3 bucket default encryption configuration and for new object uploads is available in Amazon CloudTrail logs, S3 Inventory, S3 Storage Lens, the Amazon S3 console, and as an additional Amazon S3 API response header in the Amazon Command Line Interface and Amazon SDKs. For more information, see Default encryption FAQ.

All Amazon S3 buckets have encryption configured by default, and all new objects that are uploaded to an S3 bucket are automatically encrypted at rest. Server-side encryption with Amazon S3 managed keys (SSE-S3) is the default encryption configuration for every bucket in Amazon S3. To use a different type of encryption, you can either specify the type of server-side encryption to use in your S3 PUT requests, or you can set the default encryption configuration in the destination bucket.

If you want to specify a different encryption type in your PUT requests, you can use server-side encryption with Amazon Key Management Service (Amazon KMS) keys (SSE-KMS), dual-layer server-side encryption with Amazon KMS keys (DSSE-KMS), or server-side encryption with customer-provided keys (SSE-C). If you want to set a different default encryption configuration in the destination bucket, you can use SSE-KMS or DSSE-KMS.

You can specify SSE-S3 by using the S3 console, REST APIs, Amazon SDKs, and Amazon Command Line Interface (Amazon CLI). For more information, see Setting default server-side encryption behavior for Amazon S3 buckets.

This topic describes how to set or change the type of encryption an object by using the Amazon Web Services Management Console. When you copy an object by using the console, Amazon S3 copies the object as is. That means that if the source object is encrypted, the target object is also encrypted. You can use the console to add or change encryption for an object.

Note
  • If you change an object's encryption, a new object is created to replace the old one. If S3 Versioning is enabled, a new version of the object is created, and the existing object becomes an older version. The role that changes the property also becomes the owner of the new object (or object version).

  • If you change the encryption type for an object that has user-defined tags, you must have the s3:GetObjectTagging permission. If you're changing the encryption type for an object that doesn't have user-defined tags but is over 16 MB in size, you must also have the s3:GetObjectTagging permission.

    If the destination bucket policy denies the s3:GetObjectTagging action, the encryption type for the object will be updated, but the user-defined tags will be removed from the object, and you will receive an error.

To change encryption for an object
  1. Sign in to the Amazon Web Services Management Console and open the Amazon S3 console at https://console.amazonaws.cn/s3/.

  2. In the left navigation pane, choose Buckets.

  3. In the Buckets list, choose the name of the bucket that contains the object.

  4. In the Objects list, choose the name of the object that you want to add or change encryption for.

    The object's details page appears, with several sections that display the properties for your object.

  5. Choose the Properties tab.

  6. Scroll down to the Server-side encryption settings section, and then choose Edit.

  7. Under Encryption settings, choose Use bucket default encryption settings or Override bucket default encryption settings.

  8. If you chose Override bucket settings for default encryption, configure the following encryption settings.

    1. Under Encryption type, choose Amazon S3 managed keys (SSE-S3). SSE-S3 uses one of the strongest block ciphers—256-bit Advanced Encryption Standard (AES-256) to encrypt each object. For more information, see Using server-side encryption with Amazon S3 managed keys (SSE-S3).

  9. Choose Save changes.

Note

This action applies encryption to all specified objects. When you're encrypting folders, wait for the save operation to finish before adding new objects to the folder.

At the time of object creation—that is, when you are uploading a new object or making a copy of an existing object—you can specify if you want Amazon S3 to encrypt your data with Amazon S3 managed keys (SSE-S3) by adding the x-amz-server-side-encryption header to the request. Set the value of the header to the encryption algorithm AES256, which Amazon S3 supports. Amazon S3 confirms that your object is stored with SSE-S3 by returning the response header x-amz-server-side-encryption.

The following REST upload API operations accept the x-amz-server-side-encryption request header.

When uploading large objects by using the multipart upload API operation, you can specify server-side encryption by adding the x-amz-server-side-encryption header to the Initiate Multipart Upload request. When you're copying an existing object, regardless of whether the source object is encrypted or not, the destination object is not encrypted unless you explicitly request server-side encryption.

The response headers of the following REST API operations return the x-amz-server-side-encryption header when an object is stored using SSE-S3.

Note

Do not send encryption request headers for GET requests and HEAD requests if your object uses SSE-S3, or you'll get an HTTP status code 400 (Bad Request) error.

When using Amazon SDKs, you can request Amazon S3 to use server-side encryption with Amazon S3 managed encryption keys (SSE-S3). This section provides examples of using the Amazon SDKs in multiple languages. For information about other SDKs, go to Sample Code and Libraries.

Java

When you use the Amazon SDK for Java to upload an object, you can use SSE-S3 to encrypt it. To request server-side encryption, use the ObjectMetadata property of the PutObjectRequest to set the x-amz-server-side-encryption request header. When you call the putObject() method of the AmazonS3Client, Amazon S3 encrypts and saves the data.

You can also request SSE-S3 encryption when uploading objects with the multipart upload API operation:

  • When using the high-level multipart upload API operation, you use the TransferManager methods to apply server-side encryption to objects as you upload them. You can use any of the upload methods that take ObjectMetadata as a parameter. For more information, see Uploading an object using multipart upload.

  • When using the low-level multipart upload API operation, you specify server-side encryption when you initiate the multipart upload. You add the ObjectMetadata property by calling the InitiateMultipartUploadRequest.setObjectMetadata() method. For more information, see Using the Amazon SDKs (low-level API).

You can't directly change the encryption state of an object (encrypting an unencrypted object or decrypting an encrypted object). To change an object's encryption state, you make a copy of the object, specifying the desired encryption state for the copy, and then delete the original object. Amazon S3 encrypts the copied object only if you explicitly request server-side encryption. To request encryption of the copied object through the Java API, use the ObjectMetadata property to specify server-side encryption in the CopyObjectRequest.

Example

The following example shows how to set server-side encryption by using the Amazon SDK for Java. It shows how to perform the following tasks:

  • Upload a new object by using SSE-S3.

  • Change an object's encryption state (in this example, encrypting a previously unencrypted object) by making a copy of the object.

  • Check the encryption state of the object.

For more information about server-side encryption, see Using the REST API. For instructions on creating and testing a working sample, see Getting Started in the Amazon SDK for Java Developer Guide.

import com.amazonaws.AmazonServiceException; import com.amazonaws.SdkClientException; import com.amazonaws.auth.profile.ProfileCredentialsProvider; import com.amazonaws.regions.Regions; import com.amazonaws.services.s3.AmazonS3; import com.amazonaws.services.s3.AmazonS3ClientBuilder; import com.amazonaws.services.s3.internal.SSEResultBase; import com.amazonaws.services.s3.model.*; import java.io.ByteArrayInputStream; public class SpecifyServerSideEncryption { public static void main(String[] args) { Regions clientRegion = Regions.DEFAULT_REGION; String bucketName = "*** Bucket name ***"; String keyNameToEncrypt = "*** Key name for an object to upload and encrypt ***"; String keyNameToCopyAndEncrypt = "*** Key name for an unencrypted object to be encrypted by copying ***"; String copiedObjectKeyName = "*** Key name for the encrypted copy of the unencrypted object ***"; try { AmazonS3 s3Client = AmazonS3ClientBuilder.standard() .withRegion(clientRegion) .withCredentials(new ProfileCredentialsProvider()) .build(); // Upload an object and encrypt it with SSE. uploadObjectWithSSEEncryption(s3Client, bucketName, keyNameToEncrypt); // Upload a new unencrypted object, then change its encryption state // to encrypted by making a copy. changeSSEEncryptionStatusByCopying(s3Client, bucketName, keyNameToCopyAndEncrypt, copiedObjectKeyName); } catch (AmazonServiceException e) { // The call was transmitted successfully, but Amazon S3 couldn't process // it, so it returned an error response. e.printStackTrace(); } catch (SdkClientException e) { // Amazon S3 couldn't be contacted for a response, or the client // couldn't parse the response from Amazon S3. e.printStackTrace(); } } private static void uploadObjectWithSSEEncryption(AmazonS3 s3Client, String bucketName, String keyName) { String objectContent = "Test object encrypted with SSE"; byte[] objectBytes = objectContent.getBytes(); // Specify server-side encryption. ObjectMetadata objectMetadata = new ObjectMetadata(); objectMetadata.setContentLength(objectBytes.length); objectMetadata.setSSEAlgorithm(ObjectMetadata.AES_256_SERVER_SIDE_ENCRYPTION); PutObjectRequest putRequest = new PutObjectRequest(bucketName, keyName, new ByteArrayInputStream(objectBytes), objectMetadata); // Upload the object and check its encryption status. PutObjectResult putResult = s3Client.putObject(putRequest); System.out.println("Object \"" + keyName + "\" uploaded with SSE."); printEncryptionStatus(putResult); } private static void changeSSEEncryptionStatusByCopying(AmazonS3 s3Client, String bucketName, String sourceKey, String destKey) { // Upload a new, unencrypted object. PutObjectResult putResult = s3Client.putObject(bucketName, sourceKey, "Object example to encrypt by copying"); System.out.println("Unencrypted object \"" + sourceKey + "\" uploaded."); printEncryptionStatus(putResult); // Make a copy of the object and use server-side encryption when storing the // copy. CopyObjectRequest request = new CopyObjectRequest(bucketName, sourceKey, bucketName, destKey); ObjectMetadata objectMetadata = new ObjectMetadata(); objectMetadata.setSSEAlgorithm(ObjectMetadata.AES_256_SERVER_SIDE_ENCRYPTION); request.setNewObjectMetadata(objectMetadata); // Perform the copy operation and display the copy's encryption status. CopyObjectResult response = s3Client.copyObject(request); System.out.println("Object \"" + destKey + "\" uploaded with SSE."); printEncryptionStatus(response); // Delete the original, unencrypted object, leaving only the encrypted copy in // Amazon S3. s3Client.deleteObject(bucketName, sourceKey); System.out.println("Unencrypted object \"" + sourceKey + "\" deleted."); } private static void printEncryptionStatus(SSEResultBase response) { String encryptionStatus = response.getSSEAlgorithm(); if (encryptionStatus == null) { encryptionStatus = "Not encrypted with SSE"; } System.out.println("Object encryption status is: " + encryptionStatus); } }
.NET

When you upload an object, you can direct Amazon S3 to encrypt it. To change the encryption state of an existing object, you make a copy of the object and delete the source object. By default, the copy operation encrypts the target only if you explicitly request server-side encryption of the target object. To specify SSE-S3 in the CopyObjectRequest, add the following:

ServerSideEncryptionMethod = ServerSideEncryptionMethod.AES256

For a working sample of how to copy an object, see Using the Amazon SDKs.

The following example uploads an object. In the request, the example directs Amazon S3 to encrypt the object. The example then retrieves object metadata and verifies the encryption method that was used. For information about setting up and running the code examples, see Getting Started with the Amazon SDK for .NET in the Amazon SDK for .NET Developer Guide.

using Amazon; using Amazon.S3; using Amazon.S3.Model; using System; using System.Threading.Tasks; namespace Amazon.DocSamples.S3 { class SpecifyServerSideEncryptionTest { private const string bucketName = "*** bucket name ***"; private const string keyName = "*** key name for object created ***"; // Specify your bucket region (an example region is shown). private static readonly RegionEndpoint bucketRegion = RegionEndpoint.USWest2; private static IAmazonS3 client; public static void Main() { client = new AmazonS3Client(bucketRegion); WritingAnObjectAsync().Wait(); } static async Task WritingAnObjectAsync() { try { var putRequest = new PutObjectRequest { BucketName = bucketName, Key = keyName, ContentBody = "sample text", ServerSideEncryptionMethod = ServerSideEncryptionMethod.AES256 }; var putResponse = await client.PutObjectAsync(putRequest); // Determine the encryption state of an object. GetObjectMetadataRequest metadataRequest = new GetObjectMetadataRequest { BucketName = bucketName, Key = keyName }; GetObjectMetadataResponse response = await client.GetObjectMetadataAsync(metadataRequest); ServerSideEncryptionMethod objectEncryption = response.ServerSideEncryptionMethod; Console.WriteLine("Encryption method used: {0}", objectEncryption.ToString()); } catch (AmazonS3Exception e) { Console.WriteLine("Error encountered ***. Message:'{0}' when writing an object", e.Message); } catch (Exception e) { Console.WriteLine("Unknown encountered on server. Message:'{0}' when writing an object", e.Message); } } } }
PHP

This topic shows how to use classes from version 3 of the Amazon SDK for PHP to add SSE-S3 to objects that you upload to Amazon S3. For more information about the Amazon SDK for Ruby API, go to Amazon SDK for Ruby - Version 2.

To upload an object to Amazon S3, use the Aws\S3\S3Client::putObject() method. To add the x-amz-server-side-encryption request header to your upload request, specify the ServerSideEncryption parameter with the value AES256, as shown in the following code example. For information about server-side encryption requests, see Using the REST API.

require 'vendor/autoload.php'; use Aws\S3\S3Client; $bucket = '*** Your Bucket Name ***'; $keyname = '*** Your Object Key ***'; // $filepath should be an absolute path to a file on disk. $filepath = '*** Your File Path ***'; $s3 = new S3Client([ 'version' => 'latest', 'region' => 'us-east-1' ]); // Upload a file with server-side encryption. $result = $s3->putObject([ 'Bucket' => $bucket, 'Key' => $keyname, 'SourceFile' => $filepath, 'ServerSideEncryption' => 'AES256', ]);

In response, Amazon S3 returns the x-amz-server-side-encryption header with the value of the encryption algorithm that was used to encrypt your object's data.

When you upload large objects by using the multipart upload API operation, you can specify SSE-S3 for the objects that you are uploading, as follows:

  • When you're using the low-level multipart upload API operation, specify server-side encryption when you call the Aws\S3\S3Client::createMultipartUpload() method. To add the x-amz-server-side-encryption request header to your request, specify the array parameter's ServerSideEncryption key with the value AES256. For more information about the low-level multipart upload API operation, see Using the Amazon SDKs (low-level API).

  • When you're using the high-level multipart upload API operation, specify server-side encryption by using the ServerSideEncryption parameter of the CreateMultipartUpload API operation. For an example of using the setOption() method with the high-level multipart upload API operation, see Uploading an object using multipart upload.

To determine the encryption state of an existing object, retrieve the object metadata by calling the Aws\S3\S3Client::headObject() method as shown in the following PHP code example.

require 'vendor/autoload.php'; use Aws\S3\S3Client; $bucket = '*** Your Bucket Name ***'; $keyname = '*** Your Object Key ***'; $s3 = new S3Client([ 'version' => 'latest', 'region' => 'us-east-1' ]); // Check which server-side encryption algorithm is used. $result = $s3->headObject([ 'Bucket' => $bucket, 'Key' => $keyname, ]); echo $result['ServerSideEncryption'];

To change the encryption state of an existing object, make a copy of the object by using the Aws\S3\S3Client::copyObject() method and delete the source object. By default, copyObject() does not encrypt the target unless you explicitly request server-side encryption of the destination object by using the ServerSideEncryption parameter with the value AES256. The following PHP code example makes a copy of an object and adds server-side encryption to the copied object.

require 'vendor/autoload.php'; use Aws\S3\S3Client; $sourceBucket = '*** Your Source Bucket Name ***'; $sourceKeyname = '*** Your Source Object Key ***'; $targetBucket = '*** Your Target Bucket Name ***'; $targetKeyname = '*** Your Target Object Key ***'; $s3 = new S3Client([ 'version' => 'latest', 'region' => 'us-east-1' ]); // Copy an object and add server-side encryption. $s3->copyObject([ 'Bucket' => $targetBucket, 'Key' => $targetKeyname, 'CopySource' => "$sourceBucket/$sourceKeyname", 'ServerSideEncryption' => 'AES256', ]);

For more information, see the following topics:

Ruby

When using the Amazon SDK for Ruby to upload an object, you can specify that the object be stored encrypted at rest with SSE-S3. When you read the object back, it is automatically decrypted.

The following Amazon SDK for Ruby Version 3 example demonstrates how to specify that a file uploaded to Amazon S3 be encrypted at rest.

require "aws-sdk-s3" # Wraps Amazon S3 object actions. class ObjectPutSseWrapper attr_reader :object # @param object [Aws::S3::Object] An existing Amazon S3 object. def initialize(object) @object = object end def put_object_encrypted(object_content, encryption) @object.put(body: object_content, server_side_encryption: encryption) true rescue Aws::Errors::ServiceError => e puts "Couldn't put your content to #{object.key}. Here's why: #{e.message}" false end end # Example usage: def run_demo bucket_name = "doc-example-bucket" object_key = "my-encrypted-content" object_content = "This is my super-secret content." encryption = "AES256" wrapper = ObjectPutSseWrapper.new(Aws::S3::Object.new(bucket_name, object_content)) return unless wrapper.put_object_encrypted(object_content, encryption) puts "Put your content into #{bucket_name}:#{object_key} and encrypted it with #{encryption}." end run_demo if $PROGRAM_NAME == __FILE__

The following code example demonstrates how to determine the encryption state of an existing object.

require "aws-sdk-s3" # Wraps Amazon S3 object actions. class ObjectGetEncryptionWrapper attr_reader :object # @param object [Aws::S3::Object] An existing Amazon S3 object. def initialize(object) @object = object end # Gets the object into memory. # # @return [Aws::S3::Types::GetObjectOutput, nil] The retrieved object data if successful; otherwise nil. def get_object @object.get rescue Aws::Errors::ServiceError => e puts "Couldn't get object #{@object.key}. Here's why: #{e.message}" end end # Example usage: def run_demo bucket_name = "doc-example-bucket" object_key = "my-object.txt" wrapper = ObjectGetEncryptionWrapper.new(Aws::S3::Object.new(bucket_name, object_key)) obj_data = wrapper.get_object return unless obj_data encryption = obj_data.server_side_encryption.nil? ? "no" : obj_data.server_side_encryption puts "Object #{object_key} uses #{encryption} encryption." end run_demo if $PROGRAM_NAME == __FILE__

If server-side encryption is not used for the object that is stored in Amazon S3, the method returns null.

To change the encryption state of an existing object, make a copy of the object and delete the source object. By default, the copy methods do not encrypt the target unless you explicitly request server-side encryption. You can request the encryption of the target object by specifying the server_side_encryption value in the option's hash argument, as shown in the following Ruby code example. The code example demonstrates how to copy an object and encrypt the copy with SSE-S3.

require "aws-sdk-s3" # Wraps Amazon S3 object actions. class ObjectCopyEncryptWrapper attr_reader :source_object # @param source_object [Aws::S3::Object] An existing Amazon S3 object. This is used as the source object for # copy actions. def initialize(source_object) @source_object = source_object end # Copy the source object to the specified target bucket, rename it with the target key, and encrypt it. # # @param target_bucket [Aws::S3::Bucket] An existing Amazon S3 bucket where the object is copied. # @param target_object_key [String] The key to give the copy of the object. # @return [Aws::S3::Object, nil] The copied object when successful; otherwise, nil. def copy_object(target_bucket, target_object_key, encryption) @source_object.copy_to(bucket: target_bucket.name, key: target_object_key, server_side_encryption: encryption) target_bucket.object(target_object_key) rescue Aws::Errors::ServiceError => e puts "Couldn't copy #{@source_object.key} to #{target_object_key}. Here's why: #{e.message}" end end # Example usage: def run_demo source_bucket_name = "doc-example-bucket1" source_key = "my-source-file.txt" target_bucket_name = "doc-example-bucket2" target_key = "my-target-file.txt" target_encryption = "AES256" source_bucket = Aws::S3::Bucket.new(source_bucket_name) wrapper = ObjectCopyEncryptWrapper.new(source_bucket.object(source_key)) target_bucket = Aws::S3::Bucket.new(target_bucket_name) target_object = wrapper.copy_object(target_bucket, target_key, target_encryption) return unless target_object puts "Copied #{source_key} from #{source_bucket_name} to #{target_object.bucket_name}:#{target_object.key} and "\ "encrypted the target with #{target_object.server_side_encryption} encryption." end run_demo if $PROGRAM_NAME == __FILE__

To specify SSE-S3 when you upload an object by using the Amazon CLI, use the following example.

aws s3api put-object --bucket DOC-EXAMPLE-BUCKET1 --key object-key-name --server-side-encryption AES256 --body file path

For more information, see put-object in the Amazon CLI reference. To specify SSE-S3 when you copy an object by using the Amazon CLI, see copy-object.

For examples of setting up encryption using Amazon CloudFormation, see Create a bucket with default encryption and the Create a bucket by using Amazon KMS server-side encryption with an S3 Bucket Key example in the AWS::S3::Bucket ServerSideEncryptionRule topic in the Amazon CloudFormation User Guide.