VCMP Extrinsic, Events, and Error Events

VCMP Extrinsics

VCMP extrinsic is critical to ensuring the security, privacy, and usability of verifiable credentials. The common VC management extrinsic includes request, issuance, verification, revocation, and management. Below are the Heima VCMP extrinsics and their callers:

• request_vc - VC is requested onchain- called by the user

• vc_issued - VC is issued - called by the TEE

VCMP event

VCMP events are the different events that occur during the lifecycle of a verifiable credential, such as its creation, issuance, revocation, and update. These events are important for ensuring the integrity and trustworthiness of the VC.

By tracking these events, issuers and credential holders can ensure that their verifiable credentials are up-to-date and accurate. Here are our VCM events:

pub enum Event<T: Config> {
	DelegateeAdded {
		account: T::AccountId,
	},
	DelegateeRemoved {
		account: T::AccountId,
	},
	// a VC is requested
	VCRequested {
		account: T::AccountId,
		shard: ShardIdentifier,
		assertion: Assertion,
	},
	// event that should be triggered by TEECallOrigin
	// a VC is just issued
	// we have `id_graph_hash` field since vc request could create the IDGraph
	VCIssued {
		identity: Identity,
		assertion: Assertion,
		id_graph_hash: H256,
		req_ext_hash: H256,
	},
	// Admin account was changed
	AdminChanged {
		old_admin: Option<T::AccountId>,
		new_admin: Option<T::AccountId>,
	},
	// a Schema is issued
	SchemaIssued {
		account: T::AccountId,
		shard: ShardIdentifier,
		index: SchemaIndex,
	},
	// a Schema is disabled
	SchemaDisabled {
		account: T::AccountId,
		shard: ShardIdentifier,
		index: SchemaIndex,
	},
	// a Schema is activated
	SchemaActivated {
		account: T::AccountId,
		shard: ShardIdentifier,
		index: SchemaIndex,
	},
	// a Schema is revoked
	SchemaRevoked {
		account: T::AccountId,
		shard: ShardIdentifier,
		index: SchemaIndex,
	},
	// event errors caused by processing in TEE
	// copied from core_primitives::VCMPError, we use events instead of pallet::errors,
	// see https://github.com/litentry/litentry-parachain/issues/1275
	RequestVCFailed {
		identity: Option<Identity>,
		assertion: Assertion,
		detail: ErrorDetail,
		req_ext_hash: H256,
	},
	UnclassifiedError {
		identity: Option<Identity>,
		detail: ErrorDetail,
		req_ext_hash: H256,
	},
	VCIssuedNew {
		identity: Identity,
		assertion: Assertion,
		omni_account: T::AccountId,
		req_ext_hash: H256,
	},
}

VCMP error event

A VCMP Event can be explained as any unexpected situation or issue that occurs during the process of issuing, managing, and using a VC.

It is crucial to address these errors to ensure the integrity and security of the VC management pallet. This can be achieved through implementing proper error handling mechanisms and protocols and regularly monitoring and updating the system to prevent errors from occurring in the first place. Here are the VC errors:

pub enum Error<T> {
	/// a delegatee doesn't exist
	DelegateeNotExist,
	/// a `request_vc` request from unauthorized user
	UnauthorizedUser,
	/// the VC already exists
	VCAlreadyExists,
	/// the ID doesn't exist
	VCNotExist,
	/// The requester doesn't have the permission (because of subject mismatch)
	VCSubjectMismatch,
	/// The VC is already disabled
	VCAlreadyDisabled,
	/// Error when the caller account is not the admin
	RequireAdmin,
	/// Schema not exists
	SchemaNotExists,
	/// Schema is already disabled
	SchemaAlreadyDisabled,
	/// Schema is active
	SchemaAlreadyActivated,
	SchemaIndexOverFlow,
	LengthMismatch,
}