The ecash token is an api access right token.

The token gets minted in a successful input registration api call.

The token gets redeemed for a output registration api call.

Wasabi 1.0 used chaumian blind signatures

Wasabi 1.1 used schnorr blind signatures

Wasabi 2.0 uses keyed verified anonymous credentials (wabisabi)

This allows for anonymous output registration api calls, while still ensuring that nobody can register more output than input sats.