Aliases

Why

A PATH address is opaque by design: path:4a91c2f7e8d3 names no member, network or country, and follows the subject across providers (PATH ADDRESS). Nobody reads it out over the phone.

People already pay each other by readable names: PayID, PayNow, PromptPay, the PI-SPI alias directory, a username on a payment page. PATH places such names among the identifiers of PATH ID (PIP-0007). This PIP defines one: the alias, a name a subject chooses and a network issues.

An alias does not replace the address. It is a key that FINDER resolves to the address, as a phone number is.

The identifier

A new identifier type, alias.

The network is part of the identifier. The same <name> in two networks names two identifiers, which may belong to two subjects.

Normalisation

Lower-cased and trimmed. Characters outside the form are refused, not mapped. Confusable characters are outside the form.

The separators . and _ are removed before hashing. Names that differ only by separators are one alias: awa.diop, awa_diop and awadiop are issued at most once in a network, and each spelling resolves to it. The subject's chosen spelling is the one shown.

Entering an alias

A payer enters alias:<network>:<name>, or a bare @name.

• alias:<network>:<name> designates one alias.
• A bare @name resolves in the network of the payer's member.
• A member in several networks shows the payer one match per network, each with its network, and lets the payer choose. It never picks one silently.

Issuance

• An alias is issued by the network named in it, to one subject, at the request of that subject through a member.
• One active alias per subject per network.
• Verification is the claim itself: verification_method is alias_claim, and verified_at is the time of issue.
• An alias that is held, reserved or in quarantine is not available, and the answer does not say which.
• A network publishes its reserved names in its rulebook.
• A network may mark the alias of a legal_entity subject as verified. The marker rests on a PATH ID attestation of the entity's lei or reg identifier, and the rulebook states the rule.

Discoverability

The rules of PATH ID apply unchanged: per-identifier discoverability, subject-level withdrawal, indistinguishable negatives, and the budgets of the network.

Resolution

An alias is resolved like any other key (PATH FINDER):

1. SONAR — which member holds this alias. Answered by the issuing network.
2. RESOLVER — what the destination accepts. Answered by the holding member, with standing.
3. Payee check — verify or display the name before sending (PIP-0013).

An alias never resolves to another identifier of the subject.

Changes and release

• A subject may change its alias. The number of changes in twelve months is set by the network.
• A released alias leaves the directory at once, and is not issued again before a quarantine set by the network.
• A subject that moves to another member of the same network keeps its alias. The issuing network records the new holder, and the new member registers the alias for the subject. A transfer is not a change.

Where the rules are published

The network sets the quarantine and the change limit in its rulebook. Every member's discovery document states them, with the values of its network:

"finder": {
  "aliases": { "quarantine_days": 90, "changes_per_year": 2 }
}

A member whose network issues aliases lists alias under capabilities.identifier_types.

Outside the protocol

How a member shows an alias on its own pages, for example a payment page at <host>/<name>, is a product choice. Such a page is not a PATH link: the content of a code remains https://<host>/path/<ref> (PATH INTEROP).

Interface

Errors: path.id.alias_unavailable, path.id.alias_already_held, path.id.alias_change_limit (Errors).

The SDK parses an alias with parseAlias, lists what a payer's entry designates with aliasCandidates, and formats it with displayAlias.

Compatibility

Additive. Implementations that do not know the type ignore it, as with any unknown identifier type.