Create Grant

kms_create_grant

R Documentation

Adds a grant to a KMS key

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 (describe_key) 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 create_grant 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 create_grant returns. For details, see Using a grant token in the Key Management Service Developer Guide .

• The create_grant operation also returns a GrantId. You can use the GrantId and a key identifier to identify the grant in the retire_grant and revoke_grant operations. To find the grant ID, use the list_grants or list_retirable_grants 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:

• list_grants

• list_retirable_grants

• retire_grant

• revoke_grant

Eventual consistency: The KMS API follows an eventual consistency model. For more information, see KMS eventual consistency.

Usage

kms_create_grant(KeyId, GranteePrincipal, RetiringPrincipal, Operations,
  Constraints, GrantTokens, Name, DryRun)

Arguments

KeyId

[required] 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 list_keys or describe_key.

GranteePrincipal

[required] The identity that gets the permissions specified in the grant.

To specify the grantee principal, use the Amazon Resource Name (ARN) of an Amazon Web Services principal. Valid principals include Amazon Web Services accounts, IAM users, IAM roles, federated users, and assumed role users. For help with the ARN syntax for a principal, see IAM ARNs in the Identity and Access Management User Guide .

RetiringPrincipal

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

To specify the principal, use the Amazon Resource Name (ARN) of an Amazon Web Services principal. Valid principals include Amazon Web Services accounts, IAM users, IAM roles, federated users, and assumed role users. For help with the ARN syntax for a principal, see IAM ARNs in the Identity and Access Management User Guide .

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

Operations

[required] 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 generate_data_key operation. If you try, KMS returns a ValidationError exception. For details, see Grant operations in the Key Management Service Developer Guide.

Constraints

Specifies a grant constraint.

Do not include confidential or sensitive information in this field. This field may be displayed in plaintext in CloudTrail logs and other output.

KMS supports the EncryptionContextEquals and EncryptionContextSubset grant constraints, which allow the permissions in the grant only when the encryption context in the request matches (EncryptionContextEquals) or includes (EncryptionContextSubset) the encryption context specified in the constraint.

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 describe_key and retire_grant operations, but the constraint doesn't apply to these operations. If a grant with a grant constraint includes the create_grant operation, the constraint requires that any grants created with the create_grant 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. Operations with these keys don't support an encryption context.

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 .

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 Key Management Service Developer Guide.

Name

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

Do not include confidential or sensitive information in this field. This field may be displayed in plaintext in CloudTrail logs and other output.

When this value is absent, all create_grant 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 create_grant request.

When this value is present, you can retry a create_grant 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 create_grant request, even when a duplicate GrantId is returned. All grant tokens for the same grant ID can be used interchangeably.

DryRun

Checks if your request will succeed. DryRun is an optional parameter.

To learn more about how to use this parameter, see Testing your KMS API calls in the Key Management Service Developer Guide.

Value

A list with the following syntax:

list(
  GrantToken = "string",
  GrantId = "string"
)

Request syntax

svc$create_grant(
  KeyId = "string",
  GranteePrincipal = "string",
  RetiringPrincipal = "string",
  Operations = list(
    "Decrypt"|"Encrypt"|"GenerateDataKey"|"GenerateDataKeyWithoutPlaintext"|"ReEncryptFrom"|"ReEncryptTo"|"Sign"|"Verify"|"GetPublicKey"|"CreateGrant"|"RetireGrant"|"DescribeKey"|"GenerateDataKeyPair"|"GenerateDataKeyPairWithoutPlaintext"|"GenerateMac"|"VerifyMac"|"DeriveSharedSecret"
  ),
  Constraints = list(
    EncryptionContextSubset = list(
      "string"
    ),
    EncryptionContextEquals = list(
      "string"
    )
  ),
  GrantTokens = list(
    "string"
  ),
  Name = "string",
  DryRun = TRUE|FALSE
)

Examples

## Not run: 
# The following example creates a grant that allows the specified IAM role
# to encrypt data with the specified KMS key.
svc$create_grant(
  GranteePrincipal = "arn:aws:iam::111122223333:role/ExampleRole",
  KeyId = "arn:aws:kms:us-east-2:444455556666:key/1234abcd-12ab-34cd-56ef-1234567890ab",
  Operations = list(
    "Encrypt",
    "Decrypt"
  )
)

## End(Not run)