AWS Certified Solutions Architect Associate Test 7

Server-side encryption is about protecting data at rest. Server-side encryption with Amazon S3-managed encryption keys (SSE-S3) employs strong multi-factor encryption.
Amazon S3 encrypts each object with a unique key. As an additional safeguard, it encrypts the keyitself with a master key that it regularly rotates. Amazon S3 server-side encryption uses one of thestrongest block ciphers available, 256-bit Advanced Encryption Standard (AES-256), to encrypt yourdata.
Reference: https://docs.aws.amazon.com/AmazonS3/latest/dev/UsingServerSideEncryption.html