Crate meadowcap

Meadowcap

An implementation of Meadowcap, a capability system for permissioning read and write access to the Willow data model.

Includes implementations of communal capabilities, owned capabilities, a type unifying the two, as well as the generation of McAuthorisationTokens for use with the Willow data model’s is_authorised_write parameter.

Type parameters

Willow is a parametrised family of protocols, and so this crate makes heavy use of generic parameters.

The following generic parameter names are used consistently across this crate:

• MCL - A usize representing max_component_length.
• MCC - A usize representing max_component_count.
• MPL - A usize representing max_path_length.
• NamespacePublicKey - The type used for NamespacePublicKey (willowprotocol.org), must implement the willow_data_model::NamespaceId trait.
• NamespaceSignature - The type used for NamespaceSignature (willowprotocol.org).
• UserPublicKey - The type used for UserPublicKey (willowprotocol.org), must implement the SubspaceId trait.
• UserSignature - The type used for UserSignature (willowprotocol.org).
• PD - The type used for PayloadDigest (willowprotocol.org), must implement the willow_data_model::PayloadDigest trait.

Structs

CommunalCapability

A capability which implements communal namespaces.

CommunalHandover

Can be encoded to a bytestring to be signed for a new Delegation to a CommunalCapability.

Delegation

A delegation of access rights to a user for a given area.

McAuthorisationToken

To be used as the AuthorisationToken parameter for the Willow data model.

McSubspaceCapability

A capability that certifies read access to arbitrary SubspaceIds at some unspecified non-empty willow_data_model::Path.

NamespaceIsNotCommunalError

Returned when is_communal unexpectedly mapped a given namespace to false.

NotAWriteCapabilityError

Returned when an operation only applicable to a capability with access mode AccessMode::Write was called on a capability with access mode AccessMode::Read.

OwnedCapability

A capability that implements owned namespaces.

OwnedHandover

Can be encoded to a bytestring to be signed for a new Delegation to an OwnedCapability.

PersonalPrivateInterest

SubspaceDelegation

A delegation of read access for arbitrary SubspaceIds to a UserPublicKey.

Enums

AccessMode

A mode granting read or write access to some Area.

FailedDelegationError

Returned when an attempt to delegate a capability to another UserPublicKey failed.

InvalidDelegationError

Returned when an existing delegation was an invalid successor to an existing delegation chain.

McCapability

A Meadowcap capability.

OwnedCapabilityCreationError

Returned when an attempt to create a new owned capability failed.

Traits

IsCommunal

Maps namespace public keys to booleans, determining whether that namespace of a particular willow_data_model::NamespaceId is communal or owned.

McNamespacePublicKey

An extension of NamespaceId augmented with traits required by Meadowcap.

McPublicUserKey

An extension of SubspaceId augmented with traits required by Meadowcap.