NAME

       oath_hotp_generate - API function

SYNOPSIS

       #include <oath.h>

       int  oath_hotp_generate(const  char  *  secret,  size_t  secret_length,  uint64_t moving_factor, unsigned
       digits, bool add_checksum, size_t truncation_offset, char * output_otp);

ARGUMENTS

       const char * secret
                   the shared secret string

       size_t secret_length
                   length of secret

       uint64_t moving_factor
                   a counter indicating the current OTP to generate

       unsigned digits
                   number of requested digits in the OTP, excluding checksum

       bool add_checksum
                   whether to add a checksum digit or not

       size_t truncation_offset
                   use a specific truncation offset

       char * output_otp
                   output buffer, must have room for the output OTP plus zero

DESCRIPTION

       Generate a one-time-password using the HOTP algorithm as described in RFC 4226.

       Use a value of OATH_HOTP_DYNAMIC_TRUNCATION for truncation_offset  unless  you  really  need  a  specific
       truncation offset.

       To  find out the size of the OTP you may use the OATH_HOTP_LENGTH() macro.  The output_otp buffer must be
       have room for that length plus one for the terminating NUL.

       Currently only values 6, 7 and 8 for digits are supported, and the add_checksum value is ignored.   These
       restrictions may be lifted in future versions, although some limitations are inherent in the protocol.

RETURNS

       On success, OATH_OK (zero) is returned, otherwise an error code is returned.

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.

liboath                                              2.6.11                                oath_hotp_generate(3)