Encrypting Amazon RDS resources
Amazon RDS can encrypt your Amazon RDS DB instances. Data that is encrypted at rest includes the underlying storage for DB instances, its automated backups, read replicas, and snapshots.
Amazon RDS encrypted DB instances use the industry standard AES-256 encryption algorithm to encrypt your data on the server that hosts your Amazon RDS DB instances. After your data is encrypted, Amazon RDS 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 instances, data that is in transit between the source and the read replicas is encrypted, even when replicating across AWS Regions.
Topics
Overview of encrypting Amazon RDS resources
Amazon RDS encrypted DB instances provide an additional layer of data protection by securing your data from unauthorized access to the underlying storage. You can use Amazon RDS encryption to increase data protection of your applications deployed in the cloud, and to fulfill compliance requirements for encryption at rest.
For an Amazon RDS encrypted DB instance, all logs, backups, and snapshots are encrypted. Amazon RDS uses an AWS Key Management Service 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. 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.
A read replica of an Amazon RDS encrypted instance must be encrypted using the same KMS key as the primary DB instance when both are in the same AWS Region. If the primary DB instance and read replica are in different AWS Regions, you encrypt the read replica using the KMS key for that AWS Region.
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 RDS 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
Amazon RDS also supports encrypting an Oracle or SQL Server DB instance with Transparent Data Encryption (TDE). TDE can be used with RDS encryption at rest, although using TDE and RDS encryption at rest simultaneously might slightly affect the performance of your database. You must manage different keys for each encryption method. For more information on TDE, see Oracle Transparent Data Encryption or Support for Transparent Data Encryption in SQL Server.
Encrypting a DB instance
To encrypt a new DB instance, choose Enable encryption on the Amazon RDS console. For information on creating a DB instance, see Creating an Amazon RDS DB instance.
If you use the create-db-instance AWS CLI command to create an encrypted DB
instance, set the --storage-encrypted parameter. If you use the
CreateDBInstance API operation, set the
StorageEncrypted parameter to true.
When you create an encrypted DB instance, you can choose a customer managed key or the AWS managed key for Amazon RDS to encrypt your DB instance. If you don't specify the key identifier for a customer managed key, Amazon RDS uses the AWS managed key for your new DB instance. Amazon RDS creates an AWS managed key for Amazon RDS for your AWS account. Your AWS account has a different AWS managed key for Amazon RDS 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 instance, you can't change the KMS key used by that DB instance. Therefore, be sure to determine your KMS key requirements before you create your encrypted DB instance.
If you use the AWS CLI create-db-instance command to create an
encrypted DB instance 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 RDS can lose access to the KMS key for a DB instance when you disable
the KMS key. If you lose access to a KMS key, the encrypted DB instance goes
into the inaccessible-encryption-credentials-recoverable state.
The DB instance remains in this state for seven days, during which the
instance is stopped. API calls made to the DB instance during this time might
not succeed. To recover the DB instance, enable the KMS key and restart this
DB instance. Enable the KMS key from the AWS Management Console, AWS CLI, or RDS API. Restart the DB instance using
the AWS CLI command start-db-instance or AWS Management Console.
If the DB instance isn't recovered within seven days, it goes into the
terminal inaccessible-encryption-credentials state. In this
state, the DB instance is not usable anymore and you can only restore the
DB instance 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.
During the creation of a DB instance, Amazon RDS checks if the calling principal has access to the KMS key and generates a grant from the KMS key that it uses for the entire lifetime of the DB instance. Revoking the calling principal's access to the KMS key does not affect a running database. When using KMS keys in cross-account scenarios, such as copying a snapshot to another account, the KMS key needs to be shared with the other account. If you create a DB instance from the snapshot without specifying a different KMS key, the new instance uses the KMS key from the source account. Revoking access to the key after you create the DB instance does not affect the instance. However, disabling the key impacts all DB instances encrypted with that key. To prevent this, specify a different key during the snapshot copy operation.
Determining whether encryption is turned on for a DB instance
You can use the AWS Management Console, AWS CLI, or RDS API to determine whether encryption at rest is turned on for a DB instance.
To determine whether encryption at rest is turned on for a DB instance
Sign in to the AWS Management Console and open the Amazon RDS console at https://console.aws.amazon.com/rds/
. -
In the navigation pane, choose Databases.
-
Choose the name of the DB instance that you want to check to view its details.
-
Choose the Configuration tab, and check the Encryption value under Storage.
It shows either Enabled or Not enabled.
To determine whether encryption at rest is turned on for a DB instance by using the AWS CLI, call the describe-db-instances command with the following option:
-
--db-instance-identifier– The name of the DB instance.
The following example uses a query to return either
TRUE or FALSE regarding encryption at
rest for the mydb DB instance.
Example
aws rds describe-db-instances --db-instance-identifiermydb--query "*[].{StorageEncrypted:StorageEncrypted}" --output text
To determine whether encryption at rest is turned on for a DB instance by using the Amazon RDS API, call the DescribeDBInstances operation with the following parameter:
-
DBInstanceIdentifier– The name of the DB instance.
Availability of Amazon RDS encryption
Amazon RDS encryption is currently available for all database engines and storage types, except for SQL Server Express Edition. SQL Server Express Edition supports encryption in the AWS GovCloud (US) Regions.
Amazon RDS encryption is available for most DB instance classes. The following table lists DB instance classes that don't support Amazon RDS encryption:
| Instance type | Instance class |
|---|---|
General purpose (M1) |
db.m1.small db.m1.medium db.m1.large db.m1.xlarge |
Memory optimized (M2) |
db.m2.xlarge db.m2.2xlarge db.m2.4xlarge |
Burstable (T2) |
db.t2.micro |
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 RDS encrypted DB instances
The following limitations exist for Amazon RDS encrypted DB instances:
-
You can only encrypt an Amazon RDS DB instance when you create it, not after the DB instance is created.
However, because you can encrypt a copy of an unencrypted snapshot, you can effectively add encryption to an unencrypted DB instance. That is, you can create a snapshot of your DB instance, and then create an encrypted copy of that snapshot. You can then restore a DB instance from the encrypted snapshot, and thus you have an encrypted copy of your original DB instance. For more information, see Copying a DB snapshot for Amazon RDS.
-
You can't turn off encryption on an encrypted DB instance.
-
You can't create an encrypted snapshot of an unencrypted DB instance.
-
A snapshot of an encrypted DB instance must be encrypted using the same KMS key as the DB instance.
-
You can't have an encrypted read replica of an unencrypted DB instance or an unencrypted read replica of an encrypted DB instance.
-
Encrypted read replicas must be encrypted with the same KMS key as the source DB instance when both are in the same AWS Region.
-
You can't restore an unencrypted backup or snapshot to an encrypted DB instance.
-
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 RDS 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 instance. However, you can export data from an encrypted DB instance and import the data into an unencrypted DB instance.
