Record type registry

Every credential carries a recordType number. Ids 0 to 31 are the built-in types every issuer may use (Transcript, Degree, and so on). An institution that needs something else (a workshop certificate, a micro-credential) registers its own type in RecordTypeRegistry, and the credential registry refuses any id that is neither built in nor an active custom type of that issuer.

Id ranges

uint32 public constant LAST_BUILT_IN_TYPE = 31;
uint32 public constant FIRST_CUSTOM_TYPE = 1000;
uint256 public constant MAX_NAME_BYTES = 64;
uint256 public constant MAX_DESCRIPTION_BYTES = 256;

Range	Meaning	Issuance
0 to 31	Built-in types, same meaning for every issuer	Always allowed
32 to 999	Reserved for future built-in types	Always refused (RecordTypeNotAllowed)
1000 and up	Custom types, numbered per issuer from 1000 in registration order	Allowed only for the issuer that registered the id, and only while it is active

Because custom ids are per issuer, id 1000 of one university and id 1000 of another are different types. A verifier always reads a custom name with typeOf(issuer, id).

Code and early design disagree

An early design record (ADR-0038) described 0 to 999 as built in. The contract and the app use 0 to 31 as built in and keep 32 to 999 reserved. These pages follow the code.

Built-in names

The app holds the 32 built-in names in src/types/records.ts (RECORD_TYPE_NAMES, index equals id); the contract stores no names for them.

Id	Name	Id	Name	Id	Name	Id	Name
0	Transcript	8	National ID	16	Transfer Certificate	24	Circular
1	Degree	9	Passport Copy	17	Bills	25	News
2	Marksheet	10	Character Certificate	18	Fee Receipt	26	Recommendation Letter
3	Diploma	11	Entrance Results	19	Scholarship Letter	27	Internship Certificate
4	Certificate	12	Admit Card	20	Loan Document	28	Experience Letter
5	Provisional Certificate	13	Counseling Letter	21	Hostel Clearance	29	Bonafide Certificate
6	Birth Certificate	14	Seat Allotment Letter	22	Routine	30	No Objection Certificate
7	Citizenship	15	Migration Certificate	23	Notice	31	Other

The list matches the 32 values of the v0.2 RecordType enum, so credentials of both generations use the same numbers for built-in types.

Storage in words

Mapping	Meaning
_counts[issuer]	How many custom types the issuer has registered. The next id is 1000 + count
_types[issuer][id]	RecordTypeInfo {name, description, active}
_nameTaken[issuer][keccak256(name)]	Names already used by that issuer, kept even after a type is switched off

The contract inherits only ERC165. It has no admin.

Functions

Function	Who may call	Checks	Effects	Event	Reverts
registerType(string name, string description) uint32	An active issuer	Not paused; isActiveIssuer(sender); name 1 to 64 bytes; description at most 256 bytes; name not used before by this issuer	Assigns id 1000 + count, stores the type as active	RecordTypeRegistered(issuer, id, name, description)	SystemPaused, NotIssuer, EmptyTypeName, TypeNameTooLong, TypeDescriptionTooLong, TypeNameInUse
setTypeActive(uint32 id, bool active)	The issuer that owns the id; a retired key is refused	The type exists in the caller's namespace	Changes the flag; does nothing (and emits nothing) if unchanged	RecordTypeActiveChanged(issuer, id, active)	NotIssuer, UnknownRecordType
typeOf(address issuer, uint32 id) RecordTypeInfo	Anyone (view)	The custom type exists			UnknownRecordType
typeCount(address issuer) uint32	Anyone (view)
isTypeAllowed(address issuer, uint32 id) bool	Anyone (view); called by the credential registry at issuance		True for 0 to 31, or for an existing active custom type of that issuer
contractVersion() string, supportsInterface(bytes4) bool	Anyone		"0.5.0", ERC-165

Rules that follow from the code:

• Ids are never reused, and a switched-off type keeps its name reserved for that issuer. Old credentials therefore keep a stable meaning.
• Switching a type off stops new issuance under it but leaves existing credentials untouched; their name stays readable through typeOf.
• setTypeActive keeps working while the set is paused. A removed issuer (no name) can still switch its types; a retired key cannot.
• Built-in ids cannot be passed to setTypeActive or typeOf; both revert UnknownRecordType.
• Custom types belong to the key that registered them. After a key retirement the successor starts with no custom types and registers its own.

How issuance uses it

Reserved ids 32 to 999 fall through to the second question, and since custom ids start at 1000 they never exist, so they are always refused.

How the app uses it

• /records/types lists the issuer's types and offers registration and switching (src/services/domain/record-type-service.ts: registerType, setTypeActive, typeOf). The list is rebuilt from RecordTypeRegistered and RecordTypeActiveChanged events, because the contract returns no lists.
• src/lib/record-types.ts holds the shared helpers: it classifies an id as built-in, reserved or custom and validates a new name and description before they are sent (it strips hidden characters).
• The issue form, the holder inbox and the verify page show the type name, and mark custom ones as issuer-defined.

The full flow is in Record types.

Gas

From blockchain/gas-snapshot.json: registerType 150,590; setTypeActive 32,070.

Source files

• blockchain/contracts/v03/RecordTypeRegistry.sol
• blockchain/contracts/v03/interfaces/IRecordTypeRegistry.sol
• src/services/domain/record-type-service.ts, src/lib/record-types.ts, src/types/records.ts

Tests

• blockchain/test/v03/RecordTypeRegistry.test.ts: reserved ranges, per-issuer numbering from 1000, names per issuer, ids never reused, removed issuers, bounds, owner-only switching, no event when unchanged, typeOf and isTypeAllowed
• blockchain/test/v03/CredentialRecordTypes.test.ts: issuance with built-in, active custom, reserved, unregistered, foreign and inactive ids
• blockchain/test/v03/KeyLineage.test.ts: a retired key cannot register or change a type