# Messages In this section we describe the processing of messages for the authz module. ## MsgGrant An authorization grant is created using the `MsgGrant` message. If there is already a grant for the `(granter, grantee, Authorization)` triple, then the new grant overwrites the previous one. To update or extend an existing grant, a new grant with the same `(granter, grantee, Authorization)` triple should be created. +++ https://github.com/cosmos/cosmos-sdk/blob/v0.43.0-beta1/proto/cosmos/authz/v1beta1/tx.proto#L32-L37 The message handling should fail if: * both granter and grantee have the same address. * provided `Expiration` time is less than current unix timestamp. * provided `Grant.Authorization` is not implemented. * `Authorization.MsgTypeURL()` is not defined in the router (there is no defined handler in the app router to handle that Msg types). ## MsgRevoke A grant can be removed with the `MsgRevoke` message. +++ https://github.com/cosmos/cosmos-sdk/blob/v0.43.0-beta1/proto/cosmos/authz/v1beta1/tx.proto#L60-L64 The message handling should fail if: * both granter and grantee have the same address. * provided `MsgTypeUrl` is empty. NOTE: The `MsgExec` message removes a grant if the grant has expired. ## MsgExec When a grantee wants to execute a transaction on behalf of a granter, they must send `MsgExec`. +++ https://github.com/cosmos/cosmos-sdk/blob/v0.43.0-beta1/proto/cosmos/authz/v1beta1/tx.proto#L47-L53 The message handling should fail if: * provided `Authorization` is not implemented. * grantee doesn't have permission to run the transaction. * if granted authorization is expired.