NAME

       oath_totp_validate - API function

SYNOPSIS

       #include <oath.h>

       int  oath_totp_validate(const  char  * secret, size_t secret_length, time_t now, unsigned time_step_size,
       time_t start_offset, size_t window, const char * otp);

ARGUMENTS

       const char * secret
                   the shared secret string

       size_t secret_length
                   length of secret

       time_t now  Unix time value to validate TOTP for

       unsigned time_step_size
                   time step system parameter (typically 30)

       time_t start_offset
                   Unix time of when to start counting time steps (typically 0)

       size_t window
                   how many OTPs after/before start OTP to test

       const char * otp
                   the OTP to validate.

DESCRIPTION

       Validate an OTP according to OATH TOTP algorithm per RFC 6238.

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

SINCE

       1.6.0

REPORTING BUGS

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

COPYRIGHT

       Copyright © 2009-2020 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.