Private Content Delivery

Answer - A.

The AWS Documentation mentions the following.

Use signed URLs in the following cases.

· You want to use an RTMP distribution.

Signed cookies aren't supported for RTMP distributions.

· You want to restrict access to individual files, for example, an installation download for your application.

· Your users use a client (for example, a custom HTTP client) that doesn't support cookies.

Use signed cookies in the following cases:

· You want to provide access to multiple restricted files, for example, all of the files for a video in HLS format or all of the files in the subscribers' area of a website.

· You don't want to change your current URLs.

Option B is incorrect since access here needs to be restricted for certain individual files.

Option C is incorrect since this is better for encryption purposes.

Option D is incorrect since this should be used for EC2 Instances.

For more information on a better understanding of serving private content, please refer to the below URL.

https://docs.aws.amazon.com/AmazonCloudFront/latest/DeveloperGuide/private-content-choosing-signed-urls-cookies.html

To deliver private content from S3 while ensuring that access is restricted for certain individual files, the best approach would be to use Signed URLs or Signed Cookies.

Signed URLs and Signed Cookies are both ways of authorizing access to private content in S3. They both allow you to grant time-limited access to specific objects in your S3 bucket. However, they work in slightly different ways.

Signed URLs: A signed URL is a URL that includes authentication information in the query string. This authentication information is generated by AWS and includes an expiration time, after which the URL will no longer work. When a user accesses a signed URL, they are granted temporary permission to access the object in S3.

To create a signed URL, you need to use an AWS SDK or a REST API to generate a signature for the URL. You can then distribute this URL to authorized users. Signed URLs can be used to grant access to individual files, or to all files within a folder.

Signed Cookies: Signed cookies are similar to signed URLs, but instead of including authentication information in the URL, the authentication information is stored in a browser cookie. This allows the user to access multiple objects within a bucket without having to generate a new URL for each object.

To use signed cookies, you need to create a CloudFront distribution and configure it to use a trusted signer. The trusted signer generates the authentication information and sets it in a browser cookie. The user's browser then includes this cookie in subsequent requests to the CloudFront distribution, which grants temporary permission to access the objects in S3.

Private Keys: Private keys are used for server-side encryption of objects in S3. While they can be used to restrict access to private content, they are not an ideal solution for serving private content over CloudFront. Private keys are used for encryption, not authentication, and they are not time-limited like signed URLs and cookies.

Security Groups: Security groups are a way to control inbound and outbound traffic to and from EC2 instances or other AWS resources. They are not used for serving private content from S3 via CloudFront.

In summary, the best option for delivering private content from S3 while ensuring that access is restricted for certain individual files would be to use either Signed URLs or Signed Cookies.