# Configuring encryption on EventBridge event buses
<a name="eb-encryption-event-bus-cmkey-configure"></a>

You can specify the KMS key for EventBridge to use when you create or update an event bus. You can also update the default event bus to use a customer managed key as well. 

## Specifying the AWS KMS key used for encryption when creating an event bus
<a name="eb-encryption-event-bus-cmkey-create"></a>

Choosing the AWS KMS key used for encryption is part of creating an event bus. The default is to use the AWS owned key provided by EventBridge. 

**To specify a customer managed key for encryption when creating an event bus (console)**
+ Follow these instructions:

  [Creating an event bus](eb-create-event-bus.md).

**To specify a customer managed key for encryption when creating an event bus (CLI)**
+ When calling `[create-event-bus](https://docs.aws.amazon.com/cli/latest/reference/events/create-event-bus.html)`, use the `kms-key-identifier` option to specify the customer managed key for EventBridge to use for encryption on the event bus.

  Optionally, use `dead-letter-config` to specify a dead-letter queue (DLQ).

## Updating the AWS KMS key used for encryption on an event bus
<a name="eb-encryption-event-bus-cmkey-update"></a>

You can update the AWS KMS key being used for encryption at rest on an existing event bus. This includes:
+ Changing from the default AWS owned key to a customer managed key.
+ Changing from a customer managed key to the default AWS owned key.
+ Changing from one customer managed key to another.

When you update an event bus to use a different AWS KMS key, EventBridge decrypts any data stored on the event bus and then encrypts it using the new key.

**To update the KMS key used for encryption on an event bus (console)**

1. Open the Amazon EventBridge console at [https://console.aws.amazon.com/events/](https://console.aws.amazon.com/events/).

1. In the navigation pane, choose **Event buses**.

1. Choose the event bus you want to update.

1. On the events bus details page, choose the **Encryption** tab.

1. Choose the KMS key for EventBridge to use when encrypting the event data stored on the event bus:
   + Choose **Use AWS owned key** for EventBridge to encrypt the data using an AWS owned key.

     This AWS owned key is a KMS key that EventBridge owns and manages for use in multiple AWS accounts. In general, unless you are required to audit or control the encryption key that protects your resources, an AWS owned key is a good choice. 

     This is the default.
   + Choose **Use customer managed key** for EventBridge to encrypt the data using the customer managed key that you specify or create.

     Customer managed keys are KMS keys in your AWS account that you create, own, and manage. You have full control over these KMS keys.

     1. Specify an existing customer managed key, or choose **Create a new KMS key**.

        EventBridge displays the key status and any key aliases that have been associated with the specified customer managed key.

     1. Choose the Amazon SQS queue to use as the dead-letter queue (DLQ) for this event bus, if any.

        EventBridge sends events that aren't successfully encrypted to the DLQ, if configured, so you can process them later.

**To update the KMS key used for encryption on an event bus (CLI)**
+ When calling `[update-event-bus](https://docs.aws.amazon.com/cli/latest/reference/events/create-event-bus.html)`, use the `kms-key-identifier` option to specify the customer managed key for EventBridge to use for encryption on the event bus.

  Optionally, use `dead-letter-config` to specify a dead-letter queue (DLQ).

**To update the KMS key used for encryption on the default event bus, using CloudFormation**

Because EventBridge provisions the default event bus into your account automatically, you cannot create it using a CloudFormation template, as you normally would for any resource you wanted to include in a CloudFormation stack. To include the default event bus in a CloudFormation stack, you must first *import* it into a stack. Once you have imported the default event bus into a stack, you can then update the event bus properties as desired.
+ Follow these instructions:

  [Updating a default bus using CloudFormation](event-bus-update-default-cfn.md).