Encrypting Amazon Aurora resources

Amazon Aurora can encrypt your Amazon Aurora DB clusters. Data that is encrypted at rest includes the underlying storage for DB clusters, its automated backups, read replicas, and snapshots.

Amazon Aurora encrypted DB clusters use the industry standard AES-256 encryption algorithm to encrypt your data on the server that hosts your Amazon Aurora DB clusters. After your data is encrypted, Amazon Aurora handles authentication of access and decryption of your data transparently with a minimal impact on performance. You don't need to modify your database client applications to use encryption.

Note

For encrypted and unencrypted DB clusters, data that is in transit between the source and the read replicas is encrypted, even when replicating across AWS Regions.

Overview of encrypting Amazon Aurora resources

Amazon Aurora encrypted DB clusters provide an additional layer of data protection by securing your data from unauthorized access to the underlying storage. You can use Amazon Aurora encryption to increase data protection of your applications deployed in the cloud, and to fulfill compliance requirements for encryption at rest.

For an Amazon Aurora encrypted DB cluster, all DB instances, logs, backups, and snapshots are encrypted. You can also encrypt a read replica of an Amazon Aurora encrypted cluster. Amazon Aurora uses an AWS KMS key to encrypt these resources. For more information about KMS keys, see AWS KMS keys in the AWS Key Management Service Developer Guide and AWS KMS key management. Each DB instance in the DB cluster is encrypted using the same KMS key as the DB cluster. If you copy an encrypted snapshot, you can use a different KMS key to encrypt the target snapshot than the one that was used to encrypt the source snapshot.

You can use an AWS managed key, or you can create customer managed keys. To manage the customer managed keys used for encrypting and decrypting your Amazon Aurora resources, you use the AWS Key Management Service (AWS KMS). AWS KMS combines secure, highly available hardware and software to provide a key management system scaled for the cloud. Using AWS KMS, you can create customer managed keys and define the policies that control how these customer managed keys can be used. AWS KMS supports CloudTrail, so you can audit KMS key usage to verify that customer managed keys are being used appropriately. You can use your customer managed keys with Amazon Aurora and supported AWS services such as Amazon S3, Amazon EBS, and Amazon Redshift. For a list of services that are integrated with AWS KMS, see AWS Service Integration.

Encrypting an Amazon Aurora DB cluster

To encrypt a new DB cluster, choose Enable encryption on the console. For information on creating a DB cluster, see Creating an Amazon Aurora DB cluster.

If you use the create-db-cluster AWS CLI command to create an encrypted DB cluster, set the --storage-encrypted parameter. If you use the CreateDBCluster API operation, set the StorageEncrypted parameter to true.

When you create an encrypted DB cluster, you can choose a customer managed key or the AWS managed key for Amazon Aurora to encrypt your DB cluster. If you don't specify the key identifier for a customer managed key, Amazon Aurora uses the AWS managed key for your new DB cluster. Amazon Aurora creates an AWS managed key for Amazon Aurora for your AWS account. Your AWS account has a different AWS managed key for Amazon Aurora for each AWS Region.

For more information about KMS keys, see AWS KMS keys in the AWS Key Management Service Developer Guide.

Once you have created an encrypted DB cluster, you can't change the KMS key used by that DB cluster. Therefore, be sure to determine your KMS key requirements before you create your encrypted DB cluster.

If you use the AWS CLI create-db-cluster command to create an encrypted DB cluster with a customer managed key, set the --kms-key-id parameter to any key identifier for the KMS key. If you use the Amazon RDS API CreateDBInstance operation, set the KmsKeyId parameter to any key identifier for the KMS key. To use a customer managed key in a different AWS account, specify the key ARN or alias ARN.

Important

Amazon Aurora can lose access to the KMS key for a DB cluster. For example, Aurora loses access when the KMS key isn't enabled, or when Aurora access to a KMS key is revoked. In these cases, the encrypted DB cluster goes into inaccessible-encryption-credentials-recoverable state. The DB cluster remains in this state for seven days. When you start the DB cluster during that time, it checks if the KMS key is active and recovers the DB cluster if it is. Restart the DB cluster using the AWS CLI command start-db-cluster or AWS Management Console.

If the DB cluster isn't recovered, then it goes into the terminal inaccessible-encryption-credentials state. In this case, you can only restore the DB cluster from a backup. We strongly recommend that you always turn on backups for encrypted DB instances to guard against the loss of encrypted data in your databases.

Determining whether encryption is turned on for a DB cluster

You can use the AWS Management Console, AWS CLI, or RDS API to determine whether encryption at rest is turned on for a DB cluster.

Console

To determine whether encryption at rest is turned on for a DB cluster

1. Sign in to the AWS Management Console and open the Amazon RDS console at https://console.aws.amazon.com/rds/.

2. In the navigation pane, choose Databases.

3. Choose the name of the DB cluster that you want to check to view its details.

4. Choose the Configuration tab and check the Encryption value.

   It shows either Enabled or Not enabled.

   

AWS CLI

To determine whether encryption at rest is turned on for a DB cluster by using the AWS CLI, call the describe-db-clusters command with the following option:

• --db-cluster-identifier – The name of the DB cluster.

The following example uses a query to return either TRUE or FALSE regarding encryption at rest for the mydb DB cluster.

Example

aws rds describe-db-clusters --db-cluster-identifier mydb --query "*[].{StorageEncrypted:StorageEncrypted}" --output text

RDS API

To determine whether encryption at rest is turned on for a DB cluster by using the Amazon RDS API, call the DescribeDBClusters operation with the following parameter:

• DBClusterIdentifier – The name of the DB cluster.

Availability of Amazon Aurora encryption

Amazon Aurora encryption is currently available for all database engines and storage types.

Note

Amazon Aurora encryption is not available for the db.t2.micro DB instance class.

Encryption in transit

AWS provides secure and private connectivity between DB instances of all types. In addition, some instance types use the offload capabilities of the underlying Nitro System hardware to automatically encrypt in-transit traffic between instances. This encryption uses Authenticated Encryption with Associated Data (AEAD) algorithms, with 256-bit encryption. There is no impact on network performance. To support this additional in-transit traffic encryption between instances, the following requirements must be met:

• The instances use the following instance types:

  • General purpose: M6i, M6id, M6in, M6idn, M7g

  • Memory optimized: R6i, R6id, R6in, R6idn, R7g, X2idn, X2iedn, X2iezn

• The instances are in the same AWS Region.

• The instances are in the same VPC or peered VPCs, and the traffic does not pass through a virtual network device or service, such as a load balancer or a transit gateway.

Limitations of Amazon Aurora encrypted DB clusters

The following limitations exist for Amazon Aurora encrypted DB clusters:

• You can't turn off encryption on an encrypted DB cluster.

• You can't create an encrypted snapshot of an unencrypted DB cluster.

• A snapshot of an encrypted DB cluster must be encrypted using the same KMS key as the DB cluster.

• You can't convert an unencrypted DB cluster to an encrypted one. However, you can restore an unencrypted snapshot to an encrypted Aurora DB cluster. To do this, specify a KMS key when you restore from the unencrypted snapshot.

• You can't create an encrypted Aurora Replica from an unencrypted Aurora DB cluster. You can't create an unencrypted Aurora Replica from an encrypted Aurora DB cluster.

• To copy an encrypted snapshot from one AWS Region to another, you must specify the KMS key in the destination AWS Region. This is because KMS keys are specific to the AWS Region that they are created in.

  The source snapshot remains encrypted throughout the copy process. Amazon Aurora uses envelope encryption to protect data during the copy process. For more information about envelope encryption, see Envelope encryption in the AWS Key Management Service Developer Guide.

• You can't unencrypt an encrypted DB cluster. However, you can export data from an encrypted DB cluster and import the data into an unencrypted DB cluster.