For login, the single-use authToken is spent on a call to /session/create .
This allocates two new (random 32-byte) tokens: a long-lived "sessionToken", and a single-use "keyFetchToken". The /session/create call returns an encrypted bundle containing the two tokens.
[[File:PICL-IdPAuth-encrypt-sessionToken.png|Decrypting the sessionToken and keyFetchToken]]