kmsMasterKeyId

Amazon Web Services Key Management Service (KMS) customer managed key ID to use for the default encryption.

• General purpose buckets - This parameter is allowed if and only if SSEAlgorithm is set to aws:kms or aws:kms:dsse.

• Directory buckets - This parameter is allowed if and only if SSEAlgorithm is set to aws:kms. You can specify the key ID, key alias, or the Amazon Resource Name (ARN) of the KMS key.

• Key ID: 1234abcd-12ab-34cd-56ef-1234567890ab

• Key ARN: arn:aws:kms:us-east-2:111122223333:key/1234abcd-12ab-34cd-56ef-1234567890ab

• Key Alias: alias/alias-name

If you are using encryption with cross-account or Amazon Web Services service operations, you must use a fully qualified KMS key ARN. For more information, see Using encryption for cross-account operations.

• General purpose buckets - If you're specifying a customer managed KMS key, we recommend using a fully qualified KMS key ARN. If you use a KMS key alias instead, then KMS resolves the key within the requester’s account. This behavior can result in data that's encrypted with a KMS key that belongs to the requester, and not the bucket owner. Also, if you use a key ID, you can run into a LogDestination undeliverable error when creating a VPC flow log.

• Directory buckets - When you specify an KMS customer managed key for encryption in your directory bucket, only use the key ID or key ARN. The key alias format of the KMS key isn't supported. Amazon S3 only supports symmetric encryption KMS keys. For more information, see Asymmetric keys in Amazon Web Services KMS in the Amazon Web Services Key Management Service Developer Guide.