MediaTypes

Guarantees confidentiality and integrity without revealing the identity of the sender.

A specialized combination that hides the skid header in the authcrypt envelope, so the hop immediately sourceward of a mediator cannot discover an identifier for the sender. See Protecting the Sender Identity.

Guarantees confidentiality, integrity, and non-repudiation – but prevents an observer of the outer envelope from accessing the signature. Relative to authcrypt(plaintext), this increases guarantees to the recipient, since non-repudiation is strong than simple authentication. However, it also forces the sender to talk “on the record” and is thus not assumed to be desirable by default.

Guarantees confidentiality and integrity. Also proves the identity of the sender – but in a way that only the recipient can verify. This is the default wrapping choice, and SHOULD be used unless a different goal is clearly identified. By design, this combination and all other combinations that use encryption in their outermost layer share an identical IANA media type, because only the recipient should care about the difference.

Adds no useful guarantees over the previous choice, and is slightly more expensive, so this wrapping combination SHOULD NOT be emitted by conforming implementations. However, implementations MAY accept it. If they choose to do so, they MUST emit an error if the signer of the plaintext is different from the sender identified by the authcrypt layer.

ENCRYPTED is a generic just to be used by the MediaTypes.decoder

Used as the building block of higher-level protocols, but rarely transmitted directly, since it lacks security guarantees.

Adds non-repudiation to a plaintext message; whoever receives a message wrapped in this way can prove its origin to any external party.