NAME

oath_totp_validate4 - API function

SYNOPSIS

#include <oath.h>

int oath_totp_validate4(const char * secret, size_t secret_length, time_t now, unsigned time_step_size, time_t start_offset, size_t window, int * otp_pos, uint64_t * otp_counter, int flags, 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

int * otp_pos

output search position in search window (may be NULL).

uint64_t * otp_counter

counter value used to calculate OTP value (may be NULL).

int flags

flags indicating mode, one of oath_totp_flags

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.

The flags parameter may be used to change the MAC function, for example OATH_TOTP_HMAC_SHA256 or OATH_TOTP_HMAC_SHA512.

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

2.6.0

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.