KMS applies the grant constraints only to cryptographic operations that support an encryption context, that is, all cryptographic operations with a symmetric KMS key. Grant constraints are not applied to operations that do not support an encryption context, such as cryptographic operations with asymmetric KMS keys and management operations, such as DescribeKey or RetireGrant.
In a cryptographic operation, the encryption context in the decryption operation must be an exact, case-sensitive match for the keys and values in the encryption context of the encryption operation. Only the order of the pairs can vary.
However, in a grant constraint, the key in each key-value pair is not case sensitive, but the value is case sensitive.
To avoid confusion, do not use multiple encryption context pairs that differ only by
case. To require a fully case-sensitive encryption context, use the
in an IAM or key policy. For details, see kms:EncryptionContext: in the
Key Management Service Developer Guide
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.
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.