Specifies a grant constraint.
KMS supports the
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,
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
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
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.
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.
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.
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
When this value is present, you can retry a
CreateGrant request with
identical parameters; if the grant already exists, the original
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.
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.
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.