Exploring ENUM Validation Architecture and Token Format for Efficient Number Ownership Verification

1. ENUM Validation Architecture &Token Formatdraft-mayrhofer-enum-validation-00.txt Axel Mayrhofer, Otmar Lendl enum.at GmbH Michael Haberler Internet Foundation Austria

2. overview • sources of validation information • goals + setup options • architecture • token format contents

3. sources of validation information

4. goals • prove the registrant‘s right-to-use in the number • efficient process in common cases • be easy on incumbents or they‘ll never bite • allow for consumer choice • enable ENUM service provision even if NRH is not cooperating • avoid the next monopoly • allow for many sources of validation information • may the best method win • dont tilt new versus existing number use

5. setup options • centralized validation agent • this is the next monopoly • inefficient on service providers – they know their customers already • multiple validation agents • no monopoly, but still ineffective • number range holder = registrar • „efficient“ on telcos, ITSP‘s • might leave consumer behind • conclusion: no single source works best • so: define Validation Entity as a role • VE might collapse with registrar – easy • it might not: a chain of trust is required

6. registry validation entity registrar validation entity registrant architecture registration + validation token validation request validation entity registrar validation token delegation request registrant

7. validation process • requires a chain of trust registry <-> VE • signing of token with XML-DSIG + certificate • contract between VE and registry • assigns ID, describes method, trust chain • open list of methods • regulatory requirement in +43 is by maximum failure rate only • token lifetime determines the domain visibility • token contents is an audit trail

8. token contents • token MUST contain: • validation „serial number“ • e164 number • validation entity ID • method ID • registrar for whom validation was carried out • create, expiredate • MAY contain • registrant identity: • organisation • commercial entity registration number • title, firstname, lastname, address, streetname, streetnumber, apt,zip code, country, state • phone, fax, email • identity geared towards reuse of directory information as per ITU E.115 • a superset of the hoeneisen-token

9. contacts • Alexander Mayrhofer enum.at GmbH Phone: +43 1 5056416 34 alexander.mayrhofer@enum.at • Otmar Lendl enum.at GmbH Phone: +43 1 5056416 33 otmar.lendl@enum.at • Michael Haberler Internet Foundation Austria phone +43 664 4213465 mah@eunet.at • registry specification, registrar manual, registrar toolkit, contracts available at www.enum.at