oath_hotp_validate(3)

NAME
oath_hotp_validate - API function

SYNOPSIS
#include <oath.h>

int oath_hotp_validate(const char * secret, size_t secret_length, uint64_t start_moving_factor, size_t window, const char * otp);

ARGUMENTS

const char * secret
    the shared secret string

size_t secret_length
    length of secret

uint64_t start_moving_factor
    start counter in OTP stream

size_t window
    how many OTPs after start counter to test

const char * otp
    the OTP to validate.

DESCRIPTION
Validate an OTP according to OATH HOTP algorithm per RFC 4226. Currently only OTP lengths of 6, 7 or 8 digits are supported. This restrictions may be lifted in future versions, although some limitations are inherent in the protocol.

RETURNS
Returns position in OTP window (zero is first position), or OATH_INVALID_OTP if no OTP was found in OTP window, or an error code.

REPORTING BUGS
Report bugs to <oath-toolkit-help@nongnu.org>. liboath home page: https://oath-toolkit.codeberg.page/ General help using GNU software: http://www.gnu.org/gethelp/

COPYRIGHT
Copyright © 2009-2026 Simon Josefsson.
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.