olemus
päringuvõltsingu tõrje vahend: ühene salajane ennustamatu väärtus,
mille genereerib serveripoolne rakendus ja saadab kliendile, et klient paneks ta oma järgmisse HTTP-päringusse
= a unique, secret, unpredictable value that is generated by the server-side application and transmitted to the client in such a way that it is included in a subsequent HTTP request made by the client

ülevaateid
https://portswigger.net/web-security/csrf
https://portswigger.net/web-security/csrf/tokens
https://security.openstack.org/guidelines/dg_cross-site-request-forgery-csrf.html