class Key (construct)

Language	Type name
.NET	`Amazon.CDK.AWS.KMS.Key`
Java	`software.amazon.awscdk.services.kms.Key`
Python	`aws_cdk.aws_kms.Key`
TypeScript (source)	`@aws-cdk/aws-kms` » `Key`

Implements IConstruct, IConstruct, IDependable, IResource, IKey

Defines a KMS key.

Example

import * as kms from '@aws-cdk/aws-kms';

const encryptionKey = new kms.Key(this, 'Key', {
  enableKeyRotation: true,
});
const table = new dynamodb.Table(this, 'MyTable', {
  partitionKey: { name: 'id', type: dynamodb.AttributeType.STRING },
  encryption: dynamodb.TableEncryption.CUSTOMER_MANAGED,
  encryptionKey, // This will be exposed as table.encryptionKey
});

Initializer

new Key(scope: Construct, id: string, props?: KeyProps)

Parameters

scope Construct
id string
props KeyProps

Construct Props

Name	Type	Description
admins?	`IPrincipal[]`	A list of principals to add as key administrators to the key policy.
alias?	`string`	Initial alias to add to the key.
description?	`string`	A description of the key.
enableKeyRotation?	`boolean`	Indicates whether AWS KMS rotates the key.
enabled?	`boolean`	Indicates whether the key is available for use.
keySpec?	`KeySpec`	The cryptographic configuration of the key. The valid value depends on usage of the key.
keyUsage?	`KeyUsage`	The cryptographic operations for which the key can be used.
pendingWindow?	`Duration`	Specifies the number of days in the waiting period before AWS KMS deletes a CMK that has been removed from a CloudFormation stack.
policy?	`PolicyDocument`	Custom policy document to attach to the KMS key.
removalPolicy?	`RemovalPolicy`	Whether the encryption key should be retained when it is removed from the Stack.
trustAccountIdentities?⚠️	`boolean`	Whether the key usage can be granted by IAM policies.

admins?

Type: IPrincipal[] (optional, default: [])

A list of principals to add as key administrators to the key policy.

Key administrators have permissions to manage the key (e.g., change permissions, revoke), but do not have permissions to use the key in cryptographic operations (e.g., encrypt, decrypt).

These principals will be added to the default key policy (if none specified), or to the specified policy (if provided).

alias?

Type: string (optional, default: No alias is added for the key.)

Initial alias to add to the key.

More aliases can be added later by calling addAlias.

description?

Type: string (optional, default: No description.)

A description of the key.

Use a description that helps your users decide whether the key is appropriate for a particular task.

enableKeyRotation?

Type: boolean (optional, default: false)

Indicates whether AWS KMS rotates the key.

enabled?

Type: boolean (optional, default: Key is enabled.)

Indicates whether the key is available for use.

keySpec?

Type: KeySpec (optional, default: KeySpec.SYMMETRIC_DEFAULT)

The cryptographic configuration of the key. The valid value depends on usage of the key.

IMPORTANT: If you change this property of an existing key, the existing key is scheduled for deletion and a new key is created with the specified value.

keyUsage?

Type: KeyUsage (optional, default: KeyUsage.ENCRYPT_DECRYPT)

The cryptographic operations for which the key can be used.

IMPORTANT: If you change this property of an existing key, the existing key is scheduled for deletion and a new key is created with the specified value.

pendingWindow?

Type: Duration (optional, default: 30 days)

Specifies the number of days in the waiting period before AWS KMS deletes a CMK that has been removed from a CloudFormation stack.

When you remove a customer master key (CMK) from a CloudFormation stack, AWS KMS schedules the CMK for deletion and starts the mandatory waiting period. The PendingWindowInDays property determines the length of waiting period. During the waiting period, the key state of CMK is Pending Deletion, which prevents the CMK from being used in cryptographic operations. When the waiting period expires, AWS KMS permanently deletes the CMK.

Enter a value between 7 and 30 days.

policy?

Type: PolicyDocument (optional, default: A policy document with permissions for the account root to administer the key will be created.)

Custom policy document to attach to the KMS key.

NOTE - If the @aws-cdk/aws-kms:defaultKeyPolicies feature flag is set (the default for new projects), this policy will override the default key policy and become the only key policy for the key. If the feature flag is not set, this policy will be appended to the default key policy.

removalPolicy?

Type: RemovalPolicy (optional, default: RemovalPolicy.Retain)

Whether the encryption key should be retained when it is removed from the Stack.

This is useful when one wants to retain access to data that was encrypted with a key that is being retired.

trustAccountIdentities?⚠️

⚠️ Deprecated: redundant with the @aws-cdk/aws-kms:defaultKeyPolicies feature flag

Type: boolean (optional, default: false, unless the @aws-cdk/aws-kms:defaultKeyPolicies feature flag is set.)

Whether the key usage can be granted by IAM policies.

Setting this to true adds a default statement which delegates key access control completely to the identity's IAM policy (similar to how it works for other AWS resources). This matches the default behavior when creating KMS keys via the API or console.

If the @aws-cdk/aws-kms:defaultKeyPolicies feature flag is set (the default for new projects), this flag will always be treated as 'true' and does not need to be explicitly set.

Properties

Name	Type	Description
env	`ResourceEnvironment`	The environment this resource belongs to.
keyArn	`string`	The ARN of the key.
keyId	`string`	The ID of the key (the part that looks something like: 1234abcd-12ab-34cd-56ef-1234567890ab).
node	`ConstructNode`	The construct tree node associated with this construct.
stack	`Stack`	The stack in which this resource is defined.
trustAccountIdentities	`boolean`	Optional property to control trusting account identities.
policy?	`PolicyDocument`	Optional policy document that represents the resource policy of this key.

env

Type: ResourceEnvironment

The environment this resource belongs to.

For resources that are created and managed by the CDK (generally, those created by creating new class instances like Role, Bucket, etc.), this is always the same as the environment of the stack they belong to; however, for imported resources (those obtained from static methods like fromRoleArn, fromBucketName, etc.), that might be different than the stack they were imported into.

keyArn

Type: string

The ARN of the key.

keyId

Type: string

The ID of the key (the part that looks something like: 1234abcd-12ab-34cd-56ef-1234567890ab).

node

Type: ConstructNode

The construct tree node associated with this construct.

stack

Type: Stack

The stack in which this resource is defined.

trustAccountIdentities

Type: boolean

Optional property to control trusting account identities.

If specified, grants will default identity policies instead of to both resource and identity policies. This matches the default behavior when creating KMS keys via the API or console.

policy?

Type: PolicyDocument (optional)

Optional policy document that represents the resource policy of this key.

If specified, addToResourcePolicy can be used to edit this policy. Otherwise this method will no-op.

Methods

Name	Description
addAlias(aliasName)	Defines a new alias for the key.
addToResourcePolicy(statement, allowNoOp?)	Adds a statement to the KMS key resource policy.
applyRemovalPolicy(policy)	Apply the given removal policy to this resource.
grant(grantee, ...actions)	Grant the indicated permissions on this key to the given principal.
grantAdmin(grantee)	Grant admins permissions using this key to the given principal.
grantDecrypt(grantee)	Grant decryption permissions using this key to the given principal.
grantEncrypt(grantee)	Grant encryption permissions using this key to the given principal.
grantEncryptDecrypt(grantee)	Grant encryption and decryption permissions using this key to the given principal.
toString()	Returns a string representation of this construct.
protected validate()	Validate the current construct.
static fromCfnKey(cfnKey)	Create a mutable {@link IKey} based on a low-level {@link CfnKey}.
static fromKeyArn(scope, id, keyArn)	Import an externally defined KMS Key using its ARN.
static fromLookup(scope, id, options)	Import an existing Key by querying the AWS environment this stack is deployed to.

addAlias(aliasName)

public addAlias(aliasName: string): Alias

Parameters

aliasName string

Returns

Alias

Defines a new alias for the key.

addToResourcePolicy(statement, allowNoOp?)

public addToResourcePolicy(statement: PolicyStatement, allowNoOp?: boolean): AddToResourcePolicyResult

Parameters

statement PolicyStatement — The policy statement to add.
allowNoOp boolean — If this is set to false and there is no policy defined (i.e. external key), the operation will fail. Otherwise, it will no-op.

Returns

AddToResourcePolicyResult

Adds a statement to the KMS key resource policy.

applyRemovalPolicy(policy)

public applyRemovalPolicy(policy: RemovalPolicy): void

Parameters

policy RemovalPolicy

Apply the given removal policy to this resource.

The Removal Policy controls what happens to this resource when it stops being managed by CloudFormation, either because you've removed it from the CDK application or because you've made a change that requires the resource to be replaced.

The resource can be deleted (RemovalPolicy.DESTROY), or left in your AWS account for data recovery and cleanup later (RemovalPolicy.RETAIN).

grant(grantee, ...actions)

public grant(grantee: IGrantable, ...actions: string[]): Grant

Parameters

grantee IGrantable
actions string

Returns

Grant

Grant the indicated permissions on this key to the given principal.

This modifies both the principal's policy as well as the resource policy, since the default CloudFormation setup for KMS keys is that the policy must not be empty and so default grants won't work.

grantAdmin(grantee)

public grantAdmin(grantee: IGrantable): Grant

Parameters

grantee IGrantable

Returns

Grant

Grant admins permissions using this key to the given principal.

Key administrators have permissions to manage the key (e.g., change permissions, revoke), but do not have permissions to use the key in cryptographic operations (e.g., encrypt, decrypt).

grantDecrypt(grantee)

public grantDecrypt(grantee: IGrantable): Grant

Parameters

grantee IGrantable

Returns

Grant

Grant decryption permissions using this key to the given principal.

grantEncrypt(grantee)

public grantEncrypt(grantee: IGrantable): Grant

Parameters

grantee IGrantable

Returns

Grant

Grant encryption permissions using this key to the given principal.

grantEncryptDecrypt(grantee)

public grantEncryptDecrypt(grantee: IGrantable): Grant

Parameters

grantee IGrantable

Returns

Grant

Grant encryption and decryption permissions using this key to the given principal.

toString()

public toString(): string

Returns

string

Returns a string representation of this construct.

protected validate()

protected validate(): string[]

Returns

string[]

Validate the current construct.

This method can be implemented by derived constructs in order to perform validation logic. It is called on all constructs before synthesis.

static fromCfnKey(cfnKey)

public static fromCfnKey(cfnKey: CfnKey): IKey

Parameters

cfnKey CfnKey

Returns

IKey

Create a mutable {@link IKey} based on a low-level {@link CfnKey}.

This is most useful when combined with the cloudformation-include module. This method is different than {@link fromKeyArn()} because the {@link IKey} returned from this method is mutable; meaning, calling any mutating methods on it, like {@link IKey.addToResourcePolicy()}, will actually be reflected in the resulting template, as opposed to the object returned from {@link fromKeyArn()}, on which calling those methods would have no effect.

static fromKeyArn(scope, id, keyArn)

public static fromKeyArn(scope: Construct, id: string, keyArn: string): IKey

Parameters

scope Construct — the construct that will "own" the imported key.
id string — the id of the imported key in the construct tree.
keyArn string — the ARN of an existing KMS key.

Returns

IKey

Import an externally defined KMS Key using its ARN.

static fromLookup(scope, id, options)

public static fromLookup(scope: Construct, id: string, options: KeyLookupOptions): IKey

Parameters

scope Construct
id string
options KeyLookupOptions

Returns

IKey

Import an existing Key by querying the AWS environment this stack is deployed to.

This function only needs to be used to use Keys not defined in your CDK application. If you are looking to share a Key between stacks, you can pass the Key object between stacks and use it as normal. In addition, it's not necessary to use this method if an interface accepts an IKey. In this case, Alias.fromAliasName() can be used which returns an alias that extends IKey.

Calling this method will lead to a lookup when the CDK CLI is executed. You can therefore not use any values that will only be available at CloudFormation execution time (i.e., Tokens).

The Key information will be cached in cdk.context.json and the same Key will be used on future runs. To refresh the lookup, you will have to evict the value from the cache using the cdk context command. See https://docs.aws.amazon.com/cdk/latest/guide/context.html for more information.