gnutls_hpke_decap(3)                gnutls                gnutls_hpke_decap(3)

NAME
       gnutls_hpke_decap - API function

SYNOPSIS
       #include <gnutls/hpke.h>

       int gnutls_hpke_decap(gnutls_hpke_context_t ctx, const gnutls_datum_t *
       info, const gnutls_datum_t * enc, const gnutls_privkey_t
       receiver_privkey, const gnutls_pubkey_t sender_pubkey, const
       gnutls_datum_t * psk, const gnutls_datum_t * psk_id);

ARGUMENTS
       gnutls_hpke_context_t ctx
                   The HPKE context to use for decapsulation.

       const gnutls_datum_t * info
                   The application-specific information that was included in
                   the key schedule (optional).

       const gnutls_datum_t * enc
                   A pointer to a gnutls_datum_t structure containing the
                   encapsulated key received from the sender.

       const gnutls_privkey_t receiver_privkey
                   The receiver's private key to use for decapsulation.

       const gnutls_pubkey_t sender_pubkey
                   The sender's public key for AuthDecap operation (optional).

       const gnutls_datum_t * psk
                   The pre-shared key (optional).

       const gnutls_datum_t * psk_id
                   The pre-shared key identifier (optional).

DESCRIPTION
       This function performs the decapsulation operation of HPKE. It takes
       the encapsulated key ( enc ) received from the sender and uses it along
       with the receiver's private key to derive the shared secret. It then
       uses this shared secret along with any provided application-specific
       information ( info ) to set up the necessary keys and nonces in the
       HPKE context for subsequent sealing and opening operations.

       This function must be used once per HPKE context and before any calls
       to gnutls_hpke_open().

        enc should be the same encapsulated key that was generated by
       gnutls_hpke_encap() on the sender's side.

        receiver_privkey must be a valid private key that is compatible with
       the KEM algorithm specified in the HPKE context and that corresponds to
       the receiver's public key used during encapsulation.

       For GNUTLS_HPKE_MODE_AUTH or GNUTLS_HPKE_MODE_AUTH_PSK,
        sender_pubkey must be a valid public key that can be used for
       authentication. For GNUTLS_HPKE_MODE_PSK or GNUTLS_HPKE_MODE_AUTH_PSK,
       a pre-shared key ( psk ) and its identifier ( psk_id ) must be
       supplied.

RETURNS
       0 on success, or a negative error code on failure

SINCE
       3.8.13

REPORTING BUGS
       Report bugs to <bugs@gnutls.org>.
       Home page: https://www.gnutls.org


COPYRIGHT
       Copyright (C) 2001-2023 Free Software Foundation, Inc., and others.
       Copying and distribution of this file, with or without modification,
       are permitted in any medium without royalty provided the copyright
       notice and this notice are preserved.

SEE ALSO
       The full documentation for gnutls is maintained as a Texinfo manual.
       If the /usr/share/doc/gnutls/ directory does not contain the HTML form
       visit

       https://www.gnutls.org/manual/

gnutls                              3.8.13                gnutls_hpke_decap(3)