CreateGrant - AWS Key Management Service

CreateGrant

Adds a grant to a KMS key.

A grant is a policy instrument that allows AWS principals to use KMS keys in cryptographic operations. It also can allow them to view a KMS key ( DescribeKey ) and create and manage grants. When authorizing access to a KMS key, grants are considered along with key policies and IAM policies. Grants are often used for temporary permissions because you can create one, use its permissions, and delete it without changing your key policies or IAM policies.

For detailed information about grants, including grant terminology, see Using grants in the AWS Key Management Service Developer Guide . For examples of working with grants in several programming languages, see Programming grants.

The CreateGrant operation returns a GrantToken and a GrantId.

  • When you create, retire, or revoke a grant, there might be a brief delay, usually less than five minutes, until the grant is available throughout AWS KMS. This state is known as eventual consistency. Once the grant has achieved eventual consistency, the grantee principal can use the permissions in the grant without identifying the grant.

    However, to use the permissions in the grant immediately, use the GrantToken that CreateGrant returns. For details, see Using a grant token in the AWS Key Management Service Developer Guide .

  • The CreateGrant operation also returns a GrantId. You can use the GrantId and a key identifier to identify the grant in the RetireGrant and RevokeGrant operations. To find the grant ID, use the ListGrants or ListRetirableGrants operations.

The KMS key that you use for this operation must be in a compatible key state. For details, see Key state: Effect on your KMS key in the AWS Key Management Service Developer Guide.

Cross-account use: Yes. To perform this operation on a KMS key in a different AWS account, specify the key ARN in the value of the KeyId parameter.

Required permissions: kms:CreateGrant (key policy)

Related operations:

Request Syntax

{ "Constraints": { "EncryptionContextEquals": { "string" : "string" }, "EncryptionContextSubset": { "string" : "string" } }, "GranteePrincipal": "string", "GrantTokens": [ "string" ], "KeyId": "string", "Name": "string", "Operations": [ "string" ], "RetiringPrincipal": "string" }

Request Parameters

For information about the parameters that are common to all actions, see Common Parameters.

The request accepts the following data in JSON format.

Note

In the following list, the required parameters are described first.

GranteePrincipal

The identity that gets the permissions specified in the grant.

To specify the principal, use the Amazon Resource Name (ARN) of an AWS principal. Valid AWS principals include AWS accounts (root), IAM users, IAM roles, federated users, and assumed role users. For examples of the ARN syntax to use for specifying a principal, see AWS Identity and Access Management (IAM) in the Example ARNs section of the AWS General Reference.

Type: String

Length Constraints: Minimum length of 1. Maximum length of 256.

Pattern: ^[\w+=,.@:/-]+$

Required: Yes

KeyId

Identifies the KMS key for the grant. The grant gives principals permission to use this KMS key.

Specify the key ID or key ARN of the KMS key. To specify a KMS key in a different AWS account, you must use the key ARN.

For example:

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

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

To get the key ID and key ARN for a KMS key, use ListKeys or DescribeKey .

Type: String

Length Constraints: Minimum length of 1. Maximum length of 2048.

Required: Yes

Operations

A list of operations that the grant permits.

The operation must be supported on the KMS key. For example, you cannot create a grant for a symmetric KMS key that allows the Sign operation, or a grant for an asymmetric KMS key that allows the GenerateDataKey operation. If you try, AWS KMS returns a ValidationError exception. For details, see Grant operations in the AWS Key Management Service Developer Guide.

Type: Array of strings

Valid Values: Decrypt | Encrypt | GenerateDataKey | GenerateDataKeyWithoutPlaintext | ReEncryptFrom | ReEncryptTo | Sign | Verify | GetPublicKey | CreateGrant | RetireGrant | DescribeKey | GenerateDataKeyPair | GenerateDataKeyPairWithoutPlaintext

Required: Yes

Constraints

Specifies a grant constraint.

AWS KMS supports the EncryptionContextEquals and EncryptionContextSubset grant constraints. Each constraint value can include up to 8 encryption context pairs. The encryption context value in each constraint cannot exceed 384 characters.

These grant constraints allow the permissions in the grant only when the encryption context in the request matches (EncryptionContextEquals) or includes (EncryptionContextSubset) the encryption context specified in this structure. For information about grant constraints, see Using grant constraints in the AWS Key Management Service Developer Guide. For more information about encryption context, see Encryption Context in the AWS Key Management Service Developer Guide .

The encryption context grant constraints are supported only on operations that include an encryption context. You cannot use an encryption context grant constraint for cryptographic operations with asymmetric KMS keys or for management operations, such as DescribeKey or RetireGrant .

Type: GrantConstraints object

Required: No

GrantTokens

A list of grant tokens.

Use a grant token when your permission to call this operation comes from a new grant that has not yet achieved eventual consistency. For more information, see Grant token and Using a grant token in the AWS Key Management Service Developer Guide.

Type: Array of strings

Array Members: Minimum number of 0 items. Maximum number of 10 items.

Length Constraints: Minimum length of 1. Maximum length of 8192.

Required: No

Name

A friendly name for the grant. Use this value to prevent the unintended creation of duplicate grants when retrying this request.

When this value is absent, all CreateGrant requests result in a new grant with a unique GrantId even if all the supplied parameters are identical. This can result in unintended duplicates when you retry the CreateGrant request.

When this value is present, you can retry a CreateGrant request with identical parameters; if the grant already exists, the original GrantId is returned without creating a new grant. Note that the returned grant token is unique with every CreateGrant request, even when a duplicate GrantId is returned. All grant tokens for the same grant ID can be used interchangeably.

Type: String

Length Constraints: Minimum length of 1. Maximum length of 256.

Pattern: ^[a-zA-Z0-9:/_-]+$

Required: No

RetiringPrincipal

The principal that has permission to use the RetireGrant operation to retire the grant.

To specify the principal, use the Amazon Resource Name (ARN) of an AWS principal. Valid AWS principals include AWS accounts (root), IAM users, federated users, and assumed role users. For examples of the ARN syntax to use for specifying a principal, see AWS Identity and Access Management (IAM) in the Example ARNs section of the AWS General Reference.

The grant determines the retiring principal. Other principals might have permission to retire the grant or revoke the grant. For details, see RevokeGrant and Retiring and revoking grants in the AWS Key Management Service Developer Guide.

Type: String

Length Constraints: Minimum length of 1. Maximum length of 256.

Pattern: ^[\w+=,.@:/-]+$

Required: No

Response Syntax

{ "GrantId": "string", "GrantToken": "string" }

Response Elements

If the action is successful, the service sends back an HTTP 200 response.

The following data is returned in JSON format by the service.

GrantId

The unique identifier for the grant.

You can use the GrantId in a ListGrants , RetireGrant , or RevokeGrant operation.

Type: String

Length Constraints: Minimum length of 1. Maximum length of 128.

GrantToken

The grant token.

Use a grant token when your permission to call this operation comes from a new grant that has not yet achieved eventual consistency. For more information, see Grant token and Using a grant token in the AWS Key Management Service Developer Guide.

Type: String

Length Constraints: Minimum length of 1. Maximum length of 8192.

Errors

For information about the errors that are common to all actions, see Common Errors.

DependencyTimeoutException

The system timed out while trying to fulfill the request. The request can be retried.

HTTP Status Code: 500

DisabledException

The request was rejected because the specified KMS key is not enabled.

HTTP Status Code: 400

InvalidArnException

The request was rejected because a specified ARN, or an ARN in a key policy, is not valid.

HTTP Status Code: 400

InvalidGrantTokenException

The request was rejected because the specified grant token is not valid.

HTTP Status Code: 400

KMSInternalException

The request was rejected because an internal exception occurred. The request can be retried.

HTTP Status Code: 500

KMSInvalidStateException

The request was rejected because the state of the specified resource is not valid for this request.

For more information about how key state affects the use of a KMS key, see Key state: Effect on your KMS key in the AWS Key Management Service Developer Guide .

HTTP Status Code: 400

LimitExceededException

The request was rejected because a quota was exceeded. For more information, see Quotas in the AWS Key Management Service Developer Guide.

HTTP Status Code: 400

NotFoundException

The request was rejected because the specified entity or resource could not be found.

HTTP Status Code: 400

Examples

The following examples are formatted for legibility.

Example Request

This example illustrates one usage of CreateGrant.

POST / HTTP/1.1 Host: kms.us-east-2.amazonaws.com Content-Length: 176 X-Amz-Target: TrentService.CreateGrant X-Amz-Date: 20161031T202851Z Content-Type: application/x-amz-json-1.1 Authorization: AWS4-HMAC-SHA256\ Credential=AKIAI44QH8DHBEXAMPLE/20161031/us-east-2/kms/aws4_request,\ SignedHeaders=content-type;host;x-amz-date;x-amz-target,\ Signature=84a2b3b8eb50b9bf34ba844cd5e59649fb315a16b447357ae49bf8b87774c8f7 { "Operations": [ "Encrypt", "Decrypt" ], "GranteePrincipal": "arn:aws:iam::111122223333:role/ExampleRole", "KeyId": "arn:aws:kms:us-east-2:444455556666:key/1234abcd-12ab-34cd-56ef-1234567890ab" }

Example Response

This example illustrates one usage of CreateGrant.

HTTP/1.1 200 OK Server: Server Date: Mon, 31 Oct 2016 20:28:51 GMT Content-Type: application/x-amz-json-1.1 Content-Length: 585 Connection: keep-alive x-amzn-RequestId: a2d8d452-9fa8-11e6-b30c-dbb8ea4d97c5 { "GrantId": "0c237476b39f8bc44e45212e08498fbe3151305030726c0590dd8d3e9f3d6a60", "GrantToken": "AQpAM2RhZTk1MGMyNTk2ZmZmMzEyYWVhOWViN2I1MWM4Mzc0MWFiYjc0ZDE1ODkyNGFlNTIzODZhMzgyZjBlNGY3NiKIAgEBAgB4Pa6VDCWW__MSrqnre1HIN0Grt00ViSSuUjhqOC8OT3YAAADfMIHcBgkqhkiG9w0BBwaggc4wgcsCAQAwgcUGCSqGSIb3DQEHATAeBglghkgBZQMEAS4wEQQMmqLyBTAegIn9XlK5AgEQgIGXZQjkBcl1dykDdqZBUQ6L1OfUivQy7JVYO2-ZJP7m6f1g8GzV47HX5phdtONAP7K_HQIflcgpkoCqd_fUnE114mSmiagWkbQ5sqAVV3ov-VeqgrvMe5ZFEWLMSluvBAqdjHEdMIkHMlhlj4ENZbzBfo9Wxk8b8SnwP4kc4gGivedzFXo-dwN8fxjjq_ZZ9JFOj2ijIbj5FyogDCN0drOfi8RORSEuCEmPvjFRMFAwcmwFkN2NPp89amA" }

See Also

For more information about using this API in one of the language-specific AWS SDKs, see the following: