AWS Key Management Service
AWS Key Management Service (AWS KMS) is a managed service for creating and controling encryption keys. AWS KMS is integrated with other AWS services including EBS, S3, Redshift, Elastic Transcoder, WorkMail, RDS, and others. KMS can be found under IAM in the AWS console.
Encryption keys with KMS are regional.
As a best practice, the user with key administrative permissions should be different than the user with key usage permissions.
Envelope encryption provides an extra layer of encryption. A customer master key is used to encrypt the envelope key (data key). The envelope key is used to decrypt the data.