create-grant¶

Description¶

Adds a grant to a KMS key.

A grant is a policy instrument that allows Amazon Web Services 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 Grants in KMS in the * 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 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 * 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 states of KMS keys in the Key Management Service Developer Guide .

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

Required permissions : kms:CreateGrant (key policy)

Related operations:

ListGrants
ListRetirableGrants
RetireGrant
RevokeGrant

Synopsis¶

  create-grant
--key-id <value>
--grantee-principal <value>
[--retiring-principal <value>]
--operations <value>
[--constraints <value>]
[--grant-tokens <value>]
[--name <value>]
[--cli-input-json | --cli-input-yaml]
[--generate-cli-skeleton <value>]

Options¶

--key-id (string)

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 Amazon Web Services 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 .

--grantee-principal (string)

The identity that gets the permissions specified in the grant.

To specify the principal, use the Amazon Resource Name (ARN) of an Amazon Web Services principal. Valid Amazon Web Services principals include Amazon Web Services 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 Amazon Web Services Identity and Access Management (IAM) in the Example ARNs section of the Amazon Web Services General Reference .

--retiring-principal (string)

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 Amazon Web Services principal. Valid Amazon Web Services principals include Amazon Web Services accounts (root), IAM users, federated users, and assumed role users. For examples of the ARN syntax to use for specifying a principal, see Amazon Web Services Identity and Access Management (IAM) in the Example ARNs section of the Amazon Web Services 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 Key Management Service Developer Guide .

--operations (list)

A list of operations that the grant permits.

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

(string)

Syntax:

"string" "string" ...

Where valid values are:
  Decrypt
  Encrypt
  GenerateDataKey
  GenerateDataKeyWithoutPlaintext
  ReEncryptFrom
  ReEncryptTo
  Sign
  Verify
  GetPublicKey
  CreateGrant
  RetireGrant
  DescribeKey
  GenerateDataKeyPair
  GenerateDataKeyPairWithoutPlaintext
  GenerateMac
  VerifyMac

--constraints (structure)

Specifies a grant constraint.

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. For information about grant constraints, see Using grant constraints in the Key Management Service Developer Guide . For more information about encryption context, see Encryption context in the * Key Management Service Developer Guide * .

The encryption context 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.

The encryption context grant constraints are supported only on grant operations that include an EncryptionContext parameter, such as cryptographic operations on symmetric encryption KMS keys. Grants with grant constraints can include the DescribeKey and RetireGrant operations, but the constraint doesn’t apply to these operations. If a grant with a grant constraint includes the CreateGrant operation, the constraint requires that any grants created with the CreateGrant permission have an equally strict or stricter encryption context constraint.

You cannot use an encryption context grant constraint for cryptographic operations with asymmetric KMS keys or HMAC KMS keys. These keys don’t support an encryption context.

EncryptionContextSubset -> (map)

A list of key-value pairs that must be included in the encryption context of the cryptographic operation request. The grant allows the cryptographic operation only when the encryption context in the request includes the key-value pairs specified in this constraint, although it can include additional key-value pairs.

key -> (string)

value -> (string)

EncryptionContextEquals -> (map)

A list of key-value pairs that must match the encryption context in the cryptographic operation request. The grant allows the operation only when the encryption context in the request is the same as the encryption context specified in this constraint.

key -> (string)

value -> (string)

Shorthand Syntax:

EncryptionContextSubset={KeyName1=string,KeyName2=string},EncryptionContextEquals={KeyName1=string,KeyName2=string}

JSON Syntax:

{
  "EncryptionContextSubset": {"string": "string"
    ...},
  "EncryptionContextEquals": {"string": "string"
    ...}
}

--grant-tokens (list)

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 Key Management Service Developer Guide .

(string)

Syntax:

"string" "string" ...

--name (string)

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.

--cli-input-json | --cli-input-yaml (string) Reads arguments from the JSON string provided. The JSON string follows the format provided by --generate-cli-skeleton. If other arguments are provided on the command line, those values will override the JSON-provided values. It is not possible to pass arbitrary binary values using a JSON-provided value as the string will be taken literally. This may not be specified along with --cli-input-yaml.

--generate-cli-skeleton (string) Prints a JSON skeleton to standard output without sending an API request. If provided with no value or the value input, prints a sample input JSON that can be used as an argument for --cli-input-json. Similarly, if provided yaml-input it will print a sample input YAML that can be used with --cli-input-yaml. If provided with the value output, it validates the command inputs and returns a sample output JSON for that command.

See ‘aws help’ for descriptions of global parameters.

Examples¶

To create a grant

The following create-grant example creates a grant that allows the exampleUser user to use the decrypt command on the 1234abcd-12ab-34cd-56ef-1234567890ab example CMK. The retiring principal is the adminRole role. The grant uses the EncryptionContextSubset grant constraint to allow this permission only when the encryption context in the decrypt request includes the “Department”: “IT” key-value pair.

aws kms create-grant \
    --key-id 1234abcd-12ab-34cd-56ef-1234567890ab \
    --grantee-principal arn:aws:iam::123456789012:user/exampleUser \
    --operations Decrypt \
    --constraints EncryptionContextSubset={Department=IT} \
    --retiring-principal arn:aws:iam::123456789012:role/adminRole

The output of this command includes the ID of the new grant and a grant token. You can use the ID and token to identify the grant to other AWS KMS CLI commands, including retire-grant and revoke-grant.

{
    "GrantId": "1a2b3c4d2f5e69f440bae30eaec9570bb1fb7358824f9ddfa1aa5a0dab1a59b2",
    "GrantToken": "<grant token here>"
}

To view detailed information about the grant, use the list-grants command.

For more information, see Using Grants in the AWS Key Management Service Developer Guide.

Output¶

GrantToken -> (string)

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 Key Management Service Developer Guide .

GrantId -> (string)

The unique identifier for the grant.

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

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