NAME

       fido_assert_set_authdata,          fido_assert_set_authdata_raw,         fido_assert_set_clientdata_hash,
       fido_assert_set_count,   fido_assert_set_extensions,    fido_assert_set_hmac_salt,    fido_assert_set_up,
       fido_assert_set_uv, fido_assert_set_rp, fido_assert_set_sig — set parameters of a FIDO 2 assertion

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_assert_set_authdata(fido_assert_t *assert, size_t idx, const unsigned char *ptr, size_t len);

       int
       fido_assert_set_authdata_raw(fido_assert_t *assert, size_t idx, const unsigned char *ptr, size_t len);

       int
       fido_assert_set_clientdata_hash(fido_assert_t *assert, const unsigned char *ptr, size_t len);

       int
       fido_assert_set_count(fido_assert_t *assert, size_t n);

       int
       fido_assert_set_extensions(fido_assert_t *assert, int flags);

       int
       fido_assert_set_hmac_salt(fido_assert_t *assert, const unsigned char *ptr, size_t len);

       int
       fido_assert_set_up(fido_assert_t *assert, fido_opt_t up);

       int
       fido_assert_set_uv(fido_assert_t *assert, fido_opt_t uv);

       int
       fido_assert_set_rp(fido_assert_t *assert, const char *id);

       int
       fido_assert_set_sig(fido_assert_t *assert, size_t idx, const unsigned char *ptr, size_t len);

DESCRIPTION

       The  fido_assert_set_authdata  set  of  functions  define  the  various parameters of a FIDO 2 assertion,
       allowing a fido_assert_t type  to  be  prepared  for  a  subsequent  call  to  fido_dev_get_assert(3)  or
       fido_assert_verify(3).   For  the  complete  specification  of  a  FIDO 2 assertion and the format of its
       constituent parts, please refer to the Web Authentication (webauthn) standard.

       The fido_assert_set_count() function sets the number of assertion statements in assert to n.

       The fido_assert_set_authdata()  and  fido_assert_set_sig()  functions  set  the  authenticator  data  and
       signature  parts of the statement with index idx of assert to ptr, where ptr points to len bytes.  A copy
       of ptr is made, and no references to the passed pointer are kept.  Please note that the  first  assertion
       statement of assert has an idx of 0.  The authenticator data passed to fido_assert_set_authdata() must be
       a  CBOR-encoded  byte  string,  as obtained from fido_assert_authdata_ptr().  Alternatively, a raw binary
       blob may be passed to fido_assert_set_authdata_raw().

       The fido_assert_set_clientdata_hash() and fido_assert_set_hmac_salt() functions set the client data  hash
       and  hmac-salt  parts  of  assert  to  ptr, where ptr points to len bytes.  A copy of ptr is made, and no
       references to the passed pointer are kept.

       The fido_assert_set_rp() function sets the relying party id of assert, where id is a NUL-terminated UTF-8
       string.  The content of id is copied, and no references to the passed pointer are kept.

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

       The  fido_assert_set_up()  and  fido_assert_set_uv()  functions  set  the up (user presence) and uv (user
       verification) attributes of assert.  Both are FIDO_OPT_OMIT by default, allowing the authenticator to use
       its default settings.

       Use of the fido_assert_set_authdata set of functions may happen in two distinct situations: when asking a
       FIDO device to produce a series of assertion statements, prior to  fido_dev_get_assert(3)  (i.e,  in  the
       context  of  a  FIDO client), or when verifying assertion statements using fido_assert_verify(3) (i.e, in
       the context of a FIDO server).

       For a complete description of the generation of a FIDO 2 assertion and its verification, please refer  to
       the  FIDO 2 specification.  An example of how to use the fido_assert_set_authdata set of functions can be
       found in the examples/assert.c file shipped with libfido2.

RETURN VALUES

       The fido_assert_set_authdata functions return FIDO_OK on  success.   The  error  codes  returned  by  the
       fido_assert_set_authdata set of functions are defined in <fido/err.h>.

SEE ALSO

       fido_assert_allow_cred(3), fido_assert_verify(3), fido_dev_get_assert(3)

Debian                                            May 23, 2018                       FIDO_ASSERT_SET_AUTHDATA(3)