Cryptography

English has one verb, « to authenticate », for two people doing two different things, and careful technical German splits it. Sich authentisieren is what the claimant does: the user presents a card, a PIN or a signed challenge and so lays claim to an identity. Authentifizieren is what the other side does with that claim: the server checks the proof and accepts or rejects it. One sentence can therefore carry both verbs with different subjects — Der Nutzer authentisiert sich, der Server authentifiziert ihn. Everyday German, and plenty of software menus, use authentifizieren for both, and nobody is misunderstood; but in a specification or a security audit the split is deliberate, because it says who is responsible for which step. The rest of the list keeps the same habit of precision: das Chiffrat beside der Geheimtext, and die Integrität kept firmly apart from die Vertraulichkeit.