Question: Azure provides shared access signatures ([[1](http://msdn.microsoft.com/en-us/library/windowsazure/ee395415.aspx)], [[2](http://msdn.microsoft.com/en-us/library/windowsazure/dn140255.aspx)], [[3](http://msdn.microsoft.com/en-us/library/windowsazure/dn140256.aspx)]) that can delegate access (read/write) to specific blobs/containers/tables/queues in an Azure Storage account using an access key generated through the REST API. Does AWS offer a similar feature?

Answer: 
Presigned URL in S3 is the equivalent: 
<https://docs.aws.amazon.com/AmazonS3/latest/dev/ShareObjectPreSignedURL.html>

There are also ways to generate them with SDKs not mentioned in this documentation, you can google it.

Python for example:
<https://boto3.amazonaws.com/v1/documentation/api/latest/guide/s3-presigned-urls.html>
Equivalent for shared access signature in Amazon AWS is [`Query String Authentication`](http://docs.aws.amazon.com/AmazonS3/latest/dev/S3_QSAuth.html) however it is only for Amazon S3 (equivalent to Windows Azure Blob Storage). AWS does not have anything similar to shared access signature for SimpleDB/DynamoDB (counterpart of Windows Azure Table Storage) and Simple Queue Service (counterpart of Windows Azure Queue Service). 

I also did a comparison between Amazon AWS and Windows Azure Storage Services (S3 v/s Blob Storage etc.) in a series of blog posts which you can read here: <http://gauravmantri.com/?s=Amazon+Comparing>. Thought you might find it useful.