Brief introduction :

Amazon S3 is a web service that allows developers to gain access to highly scalable, very reliable, and inexpensive storage space. Amazon S3 is highly economical because you pay only for what you use. Data is replicated to multiple servers at multiple data centers.

Files or data that you want to store on Amazon S3 are called Objects . Once an object is stored in S3, it will contain- (1) contents of the file, and (2) the given amount of meta-data. The given Object can be from 1byte to 5GB.

Buckets provide unique namespaces for management of objects contained in the bucket. Bucket namespaces are Global across all of the S3. An S3 account is allowed 100 buckets.

A key is a unique identifier for an object within a bucket

Amazon S3 authentication ensures that nobody else sees your private data. 

• Access Key ID:  Access Key ID is a unique identifier that tells S3 to target a specific user account.
• Secret Access Key: Secret Access Key is used to access control on the given Access Key ID. You can grant various access models for an Object or an entire Bucket
  • private
  • public-read
  • public-read-write
  • authenticated-read

Secret Access Key tells S3 for what type of access control you have on given Access Key ID.