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FIDO_ASSERT_SET_AUTHDATA(3)                           Library Functions Manual

NAME
     fido_assert_set_authdata, fido_assert_set_authdata_raw,
     fido_assert_set_clientdata, fido_assert_set_clientdata_hash,
     fido_assert_set_count, fido_assert_set_extensions,
     fido_assert_set_hmac_salt, fido_assert_set_hmac_secret,
     fido_assert_set_up, fido_assert_set_uv, fido_assert_set_rp,
     fido_assert_set_sig - set parameters of a FIDO2 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(fido_assert_t *assert,
         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_hmac_secret(fido_assert_t *assert, size_t idx,
         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 FIDO2 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 FIDO2
     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() function sets the client data hash
     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_clientdata() function allows an application to set
     the client data hash of assert by specifying the assertion's unhashed
     client data.  This is required by Windows Hello, which calculates the
     client data hash internally.  For compatibility with Windows Hello,
     applications should use fido_assert_set_clientdata() instead of
     fido_assert_set_clientdata_hash().

     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_CRED_BLOB,
     FIDO_EXT_HMAC_SECRET, and FIDO_EXT_LARGEBLOB_KEY extensions are
     supported.  If flags is zero, the extensions of assert are cleared.

     The fido_assert_set_hmac_salt() and fido_assert_set_hmac_secret()
     functions set the hmac-salt and hmac-secret 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 HMAC Secret (hmac-secret) Extension is a
     CTAP 2.0 extension.  Note that the resulting hmac-secret varies according
     to whether user verification was performed by the authenticator.  The
     fido_assert_set_hmac_secret() function is normally only useful when
     writing tests.

     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 FIDO2 device to produce a series of
     assertion statements, prior to fido_dev_get_assert(3) (i.e, in the
     context of a FIDO2 client), or when verifying assertion statements using
     fido_assert_verify(3) (i.e, in the context of a FIDO2 server).

     For a complete description of the generation of a FIDO2 assertion and its
     verification, please refer to the FIDO2 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)

NetBSD 10.99              $Mdocdate: April 27 2022 $              NetBSD 10.99