Developing with Amazon S3 using the Amazon SDKs

Amazon software development kits (SDKs) are available for many popular programming languages. Each SDK provides an API, code examples, and documentation that make it easier for developers to build applications in their preferred language.

SDK Programming interfaces

Each Amazon SDK provides one or more programmatic interfaces for working with Amazon S3. Each SDK provides a low-level interface for Amazon S3, with methods that closely resemble API operations. Some SDKs provide high-level interfaces for Amazon S3, that are abstractions intended to simplify common use cases.

For example, when you perform a multipart upload by using the low-level API operations, you need to use an operation to initiate the upload, another operation to upload parts, and a final operation to complete the upload. A high-level multipart upload API operation allows you to do all of the operations required for upload in a single API call. For examples, see Uploading an object using multipart upload.

Low-level API operations allow greater control over the upload. We recommend that you use the low-level API operations if you need to pause and resume uploads, vary part sizes during the upload, or begin uploads when you don't know the size of the data in advance.

Specifying the Signature Version in Request Authentication

Amazon S3 supports only Amazon Signature Version 4 in most Amazon Web Services Regions. In some of the older Amazon Web Services Regions, Amazon S3 supports both Signature Version 4 and Signature Version 2. However, Signature Version 2 is being turned off (deprecated). For more information about the end of support for Signature Version 2, see Amazon Signature Version 2 Turned Off (Deprecated) for Amazon S3.

For a list of all the Amazon S3 Regions and the signature versions they support, see Regions and Endpoints in the Amazon General Reference.

For all Amazon Web Services Regions, Amazon SDKs use Signature Version 4 by default to authenticate requests. When using Amazon SDKs that were released before May 2016, you might be required to request Signature Version 4, as shown in the following table.

$ aws configure set default.s3.signature_version s3v4

$ aws configure set profile.your_profile_name.s3.signature_version s3v4

System.setProperty(SDKGlobalConfiguration.ENABLE_S3_SIGV4_SYSTEM_PROPERTY, "true");

-Dcom.amazonaws.services.s3.enableV4

var s3 = new AWS.S3({signatureVersion: 'v4'});

<?php 
$client = S3Client::factory([
    'region' => 'YOUR-REGION',
    'version' => 'latest',
    'signature' => 'v4'
]);

<?php 
$s3 = new Aws\S3\S3Client([
    'version' => '2006-03-01',
    'region' => 'YOUR-REGION',
    'signature_version' => 'v4'
]);

s3 = AWS::S3::Client.new(:s3_signature_version => :v4)

s3 = Aws::S3::Client.new(signature_version: 'v4')

AWSConfigsS3.UseSignatureVersion4 = true;

<appSettings>
   <add key="AWS.S3.UseSignatureVersion4" value="true" />
</appSettings>

Amazon Signature Version 2 Turned Off (Deprecated) for Amazon S3

Signature Version 2 is being turned off (deprecated) in Amazon S3. Amazon S3 will then only accept API requests that are signed using Signature Version 4.

This section provides answers to common questions regarding the end of support for Signature Version 2.

What is Signature Version 2/4, and What Does It Mean to Sign Requests?

The Signature Version 2 or Signature Version 4 signing process is used to authenticate your Amazon S3 API requests. Signing requests enables Amazon S3 to identify who is sending the request and protects your requests from bad actors.

For more information about signing Amazon requests, see Signing Amazon API Requests in the Amazon Web Services General Reference.

What Update Are You Making?

We currently support Amazon S3 API requests that are signed using Signature Version 2 and Signature Version 4 processes. After that, Amazon S3 will only accept requests that are signed using Signature Version 4.

For more information about signing Amazon requests, see Changes in Signature Version 4 in the Amazon Web Services General Reference.

Why Are You Making the Update?

Signature Version 4 provides improved security by using a signing key instead of your secret access key. Signature Version 4 is currently supported in all Amazon Web Services Regions, whereas Signature Version 2 is only supported in Regions that were launched before January 2014. This update allows us to provide a more consistent experience across all Regions.

How Do I Ensure That I'm Using Signature Version 4, and What Updates Do I Need?

The signature version that is used to sign your requests is usually set by the tool or the SDK on the client side. By default, the latest versions of our Amazon SDKs use Signature Version 4. For third-party software, contact the appropriate support team for your software to confirm what version you need. If you are sending direct REST calls to Amazon S3, you must modify your application to use the Signature Version 4 signing process.

For information about which version of the Amazon SDKs to use when moving to Signature Version 4, see Moving from Signature Version 2 to Signature Version 4.

For information about using Signature Version 4 with the Amazon S3 REST API, see Authenticating Requests (Amazon Signature Version 4) in the Amazon Simple Storage Service API Reference.

What Happens if I Don't Make Updates?

Requests signed with Signature Version 2 that are made after that will fail to authenticate with Amazon S3. Requesters will see errors stating that the request must be signed with Signature Version 4.

Should I Make Changes Even if I’m Using a Presigned URL That Requires Me to Sign for More than 7 Days?

If you are using a presigned URL that requires you to sign for more than 7 days, no action is currently needed. You can continue to use Amazon Signature Version 2 to sign and authenticate the presigned URL. We will follow up and provide more details on how to migrate to Signature Version 4 for a presigned URL scenario.

More Info

Moving from Signature Version 2 to Signature Version 4

If you currently use Signature Version 2 for Amazon S3 API request authentication, you should move to using Signature Version 4. Support is ending for Signature Version 2, as described in Amazon Signature Version 2 Turned Off (Deprecated) for Amazon S3.

For information about using Signature Version 4 with the Amazon S3 REST API, see Authenticating Requests (Amazon Signature Version 4) in the Amazon Simple Storage Service API Reference.

The following table lists the SDKs with the necessary minimum version to use Signature Version 4 (SigV4). If you are using presigned URLs with the Amazon Java, JavaScript (Node.js), or Python (Boto/CLI) SDKs, you must set the correct Amazon Web Services Region and set Signature Version 4 in the client configuration. For information about setting SigV4 in the client configuration, see Specifying the Signature Version in Request Authentication.

Amazon Tools for Windows PowerShell or Amazon Tools for PowerShell Core

If you are using module versions earlier than 3.3.0.0, you must upgrade to 3.3.0.0.

To get the version information, use the Get-Module cmdlet:

          Get-Module –Name AWSPowershell
          Get-Module –Name AWSPowershell.NetCore  
        

To update the 3.3.0.0 version, use the Update-Module cmdlet:

          Update-Module –Name AWSPowershell
          Update-Module –Name AWSPowershell.NetCore  
        

You can use presigned URLs that are valid for more than 7 days that you will send Signature Version 2 traffic on.