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

When you use the AWS 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:

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.

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);
    }
}

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 AWS 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 AWS SDK for .NET in the AWS 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);
            }
        }
    }
}

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

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.