TEL Event Types

The Transaction Event Log (TEL) manages credential registries and the credential lifecycle. Unlike the KEL, which tracks identifier key state, the TEL tracks the issuance and revocation status of verifiable credentials.

TEL events fall into three categories: registry management, backerless credential lifecycle (simple), and backed credential lifecycle.

All events share common fields: v (version string), t (type), d (SAID), i (identifier), and s (sequence number). Non-inception events also carry p (prior event SAID) to form the hash chain.

The i field meaning differs by category: for registry events (vcp/vrt) it is the registry SAID, while for credential events (iss/rev/bis/brv) it is the credential SAID.

The build pattern is always: build → computeSaid → sign.

Key differences from KEL events

• TEL manages credential registries and credential lifecycle, not identifier key state.
• Registry events (vcp/vrt) use backers instead of witnesses.
• Credential events reference registries via ri (backerless) or an ra seal (backed).
• The i field identifies the registry or credential, not an AID.

vcp — Registry Inception

Creates a new credential registry. The registry identifier equals the inception event's SAID (i === d). Sets the issuer (ii), backers (b), backer threshold (bt), and configuration traits (c).

This is always sequence 0 and has no p field — it is the root of the registry's event chain.

import { TELEvents } from '@kerits/core';

const { unsignedEvent } = TELEvents.buildVcp({
  issuerAid: myAid,
  backers: [backerAid],
  backerThreshold: '1',
  config: [],
});

// isInception = true → sets i = d
const { event, said } = TELEvents.computeSaid(unsignedEvent, true);

vrt — Registry Rotation

Rotates the backer set for an existing registry. Carries br (backers removed) and ba (backers added) delta fields, mirroring how KEL rotation uses witness deltas.

import { TELEvents } from '@kerits/core';

const { unsignedEvent } = TELEvents.buildVrt({
  registryId: vcpEvent.i,
  sequence: TELEvents.nextSequence(vcpEvent.s),
  priorEventSaid: vcpEvent.d,
  backerThreshold: '2',
  backersRemoved: [],
  backersAdded: [newBackerAid],
});

const { event } = TELEvents.computeSaid(unsignedEvent);

iss — Simple Issuance

Issues a credential without backers. Used when the registry was created with no backer configuration. The i field is the credential SAID, and ri references the registry.

This has no p field — it is the first event in the credential's TEL.

import { TELEvents } from '@kerits/core';

const { unsignedEvent } = TELEvents.buildIss({
  credentialSaid: acdcSaid,
  registryId: vcpEvent.i,
  sequence: TELEvents.nextSequence(priorEvent.s),
  datetime: new Date().toISOString(),
});

const { event } = TELEvents.computeSaid(unsignedEvent);

rev — Simple Revocation

Revokes a previously issued backerless credential. Carries the same fields as iss plus p (prior event SAID) to chain back to the issuance event.

import { TELEvents } from '@kerits/core';

const { unsignedEvent } = TELEvents.buildRev({
  credentialSaid: acdcSaid,
  registryId: vcpEvent.i,
  sequence: TELEvents.nextSequence(priorEvent.s),
  priorEventSaid: priorEvent.d,
  datetime: new Date().toISOString(),
});

const { event } = TELEvents.computeSaid(unsignedEvent);

bis — Backed Issuance

Issues a credential with backer witnesses. Instead of a simple ri registry reference, it carries an ra registry anchor seal ({ i, s, d }) that binds the credential to a specific registry event. Also includes ii (issuer AID).

This has no p field — it is the first event in the credential's TEL.

import { TELEvents } from '@kerits/core';

const { unsignedEvent } = TELEvents.buildBis({
  credentialSaid: acdcSaid,
  issuerAid: myAid,
  registrySeal: { i: vcpEvent.i, s: vcpEvent.s, d: vcpEvent.d },
  sequence: TELEvents.nextSequence(priorEvent.s),
  datetime: new Date().toISOString(),
});

const { event } = TELEvents.computeSaid(unsignedEvent);

brv — Backed Revocation

Revokes a backed credential. Carries the same fields as bis but with p (prior event SAID) and without ii. The ra seal references the registry event at the time of revocation.

import { TELEvents } from '@kerits/core';

const { unsignedEvent } = TELEvents.buildBrv({
  credentialSaid: acdcSaid,
  registrySeal: { i: vcpEvent.i, s: priorEvent.s, d: priorEvent.d },
  sequence: TELEvents.nextSequence(priorEvent.s),
  priorEventSaid: priorEvent.d,
  datetime: new Date().toISOString(),
});

const { event } = TELEvents.computeSaid(unsignedEvent);