Specifying Server-Side Encryption Using the AWS SDK for Java - Amazon Simple Storage Service

Specifying Server-Side Encryption Using the AWS SDK for Java

When you use the AWS SDK for Java to upload an object, you can use server-side encryption 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 server-side encryption when uploading objects with the multipart upload API:

  • When using the high-level multipart upload API, 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 Using the AWS Java SDK for multipart upload (high-level API).

  • When using the low-level multipart upload API, 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 Upload a file.

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.


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

  • Upload a new object using server-side encryption.

  • 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 Specifying Server-Side Encryption Using the REST API. For instructions on creating and testing a working sample, see Testing the Amazon S3 Java Code Examples.

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); } }