NAME

       fido_cred_set_authdata,      fido_cred_set_authdata_raw,      fido_cred_set_x509,      fido_cred_set_sig,
       fido_cred_set_clientdata_hash,    fido_cred_set_rp,     fido_cred_set_user,     fido_cred_set_extensions,
       fido_cred_set_rk,  fido_cred_set_uv,  fido_cred_set_fmt,  fido_cred_set_type — set parameters of a FIDO 2
       credential

SYNOPSIS

       #include <fido.h>

       typedef enum {
               FIDO_OPT_OMIT = 0, /* use authenticator's default */
               FIDO_OPT_FALSE,    /* explicitly set option to false */
               FIDO_OPT_TRUE,     /* explicitly set option to true */
       } fido_opt_t;

       int
       fido_cred_set_authdata(fido_cred_t *cred, const unsigned char *ptr, size_t len);

       int
       fido_cred_set_authdata_raw(fido_cred_t *cred, const unsigned char *ptr, size_t len);

       int
       fido_cred_set_x509(fido_cred_t *cred, const unsigned char *ptr, size_t len);

       int
       fido_cred_set_sig(fido_cred_t *cred, const unsigned char *ptr, size_t len);

       int
       fido_cred_set_clientdata_hash(fido_cred_t *cred, const unsigned char *ptr, size_t len);

       int
       fido_cred_set_rp(fido_cred_t *cred, const char *id, const char *name);

       int
       fido_cred_set_user(fido_cred_t *cred, const unsigned char *user_id, size_t user_id_len, const char *name,
           const char *display_name, const char *icon);

       int
       fido_cred_set_extensions(fido_cred_t *cred, int flags);

       int
       fido_cred_set_rk(fido_cred_t *cred, fido_opt_t rk);

       int
       fido_cred_set_uv(fido_cred_t *cred, fido_opt_t uv);

       int
       fido_cred_set_fmt(fido_cred_t *cred, const char *ptr);

       int
       fido_cred_set_type(fido_cred_t *cred, int cose_alg);

DESCRIPTION

       The fido_cred_set_authdata set of functions define  the  various  parameters  of  a  FIDO  2  credential,
       allowing  a  fido_cred_t  type  to  be  prepared  for  a  subsequent  call  to  fido_dev_make_cred(3)  or
       fido_cred_verify(3).  For the complete specification of a  FIDO  2  credential  and  the  format  of  its
       constituent parts, please refer to the Web Authentication (webauthn) standard.

       The         fido_cred_set_authdata(),        fido_cred_set_x509(),        fido_cred_set_sig(),        and
       fido_cred_set_clientdata_hash() functions set the authenticator data, attestation certificate,  signature
       and  client data hash parts of cred to ptr, where ptr points to len bytes.  A copy of ptr is made, and no
       references to the passed pointer are kept.  The authenticator  data  passed  to  fido_cred_set_authdata()
       must  be  a  CBOR-encoded  byte  string, as obtained from fido_cred_authdata_ptr().  Alternatively, a raw
       binary blob may be passed to fido_cred_set_authdata_raw().

       The fido_cred_set_rp() function sets the relying party id and name parameters of cred, where id and  name
       are  NUL-terminated  UTF-8  strings.   The  contents  of id and name are copied, and no references to the
       passed pointers are kept.

       The fido_cred_set_user() function sets the user attributes of cred, where user_id points  to  user_id_len
       bytes  and name, display_name, and icon are NUL-terminated UTF-8 strings.  The contents of user_id, name,
       display_name, and icon are copied, and no references to the passed pointers  are  kept.   Previously  set
       user attributes are flushed.  The user_id, name, display_name, and icon parameters may be NULL.

       The fido_cred_set_extensions() function sets the extensions of cred to the bitmask flags.  At the moment,
       only  the  FIDO_EXT_HMAC_SECRET  extension  is  supported.   If flags is zero, the extensions of cred are
       cleared.

       The fido_cred_set_rk()  and  fido_cred_set_uv()  functions  set  the  rk  (resident  key)  and  uv  (user
       verification)  attributes  of cred.  Both are FIDO_OPT_OMIT by default, allowing the authenticator to use
       its default settings.

       The fido_cred_set_fmt() function sets the format of cred to fmt, where fmt must  be  either  packed  (the
       format used in FIDO 2) or fido-u2f (the format used by U2F).  A copy of fmt is made, and no references to
       the  passed  pointer  are  kept.  Note that not all authenticators support FIDO2 and therefore may not be
       able to generate packed.

       The fido_cred_set_type() function sets the type of  cred  to  cose_alg,  where  cose_alg  is  COSE_ES256,
       COSE_RS256,  or  COSE_EDDSA.   The  type  of  a  credential  may  only  be  set  once.  Note that not all
       authenticators support COSE_RS256 or COSE_EDDSA.

       Use of the fido_cred_set_authdata set of functions may happen in two distinct situations: when generating
       a new credential on a FIDO device, prior to fido_dev_make_cred(3) (i.e, in the context of a FIDO client),
       or when validating a generated credential using fido_cred_verify(3)  (i.e,  in  the  context  of  a  FIDO
       server).

       For a complete description of the generation of a FIDO 2 credential and its verification, please refer to
       the  FIDO 2 specification.  A concrete utilisation example of the fido_cred_set_authdata set of functions
       can be found in the cred.c example shipped with libfido2.

RETURN VALUES

       The error codes returned by the fido_cred_set_authdata set of functions are defined in <fido/err.h>.   On
       success, FIDO_OK is returned.

SEE ALSO

       fido_cred_exclude(3), fido_cred_verify(3), fido_dev_make_cred(3)

Debian                                            May 23, 2018                         FIDO_CRED_SET_AUTHDATA(3)