Data Encryption at rest

AWS services that store data enable you to encrypt your data using Server Side Encryption, so that the customer effort is minimal, that’s why Werner Vogels, Amazon.com CTO often says “Encrypt everything”.

Ensure all critical data in your organization is encrypted. It’s recommended that you encrypt all sensitive data using your own encryption key instead of using AWS encryption keys, for that we provide a service called AWS Key Management Service.

There are plenty of benefits of having your own Key.

  • You have control over the key (you can disable it)
  • You can share your key across accounts (useful for sharing snapshots with the incident response team)
  • You can configure rotation with custom intervals according to your compliance needs.

How to make sure my resources are encrypted at scale?

An easy way to check for resources that are not encrypted in your organization is using the following checks on AWS Security Hub :

These controls are available on the AWS Security Hub NIST SP 800-53 security standard , and there are also many other controls to check for encryption in other type of resources such as DynamoDB, DocumentDB, clusters, OpenSearch, EKS Secrets, etc.

When should I choose CloudHSM over KMS ?

If you require a dedicated Hardware Security Module for your organization, otherwise use KMS instead, as it is more cost effective, it provides Multi-AZ High availability and it’s also backed by Hardware HSMs that are tamper proof. If you use CloudHSM in production, remember to create a cluster for High Availability.

If you use your own CloudHSMs remember to set up a cluster with nodes in Multiple Availability Zones.

Unless you have a very good reason to do so, avoid the following options for Key material origin:

  • External (Import Key material) - You create and import the key material for the KMS key.
  • External key store - The key material for the KMS key is in an external key manager outside of AWS.

We generally advice against these options because of the security and durability implications

Additional information in the following whitepaper

https://d1.awsstatic.com/whitepapers/KMS-Cryptographic-Details.pdf

Pricing

https://aws.amazon.com/kms/pricing
AWS Free Tier includes 20,000 free AWS KMS requests each month.

re:Invent Session: Using KMS for data protection, access control, and audit