1oath_totp_validate4(3)              liboath             oath_totp_validate4(3)
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NAME

6       oath_totp_validate4 - API function
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SYNOPSIS

9       #include <oath.h>
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11       int  oath_totp_validate4(const  char  *  secret,  size_t secret_length,
12       time_t now, unsigned time_step_size, time_t start_offset,  size_t  win‐
13       dow,  int  *  otp_pos,  uint64_t * otp_counter, int flags, const char *
14       otp);
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ARGUMENTS

17       const char * secret
18                   the shared secret string
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20       size_t secret_length
21                   length of secret
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23       time_t now  Unix time value to validate TOTP for
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25       unsigned time_step_size
26                   time step system parameter (typically 30)
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28       time_t start_offset
29                   Unix time of when to start counting time  steps  (typically
30                   0)
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32       size_t window
33                   how many OTPs after/before start OTP to test
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35       int * otp_pos
36                   output search position in search window (may be NULL).
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38       uint64_t * otp_counter
39                   counter value used to calculate OTP value (may be NULL).
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41       int flags   flags indicating mode, one of oath_totp_flags
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43       const char * otp
44                   the OTP to validate.
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DESCRIPTION

47       Validate an OTP according to OATH TOTP algorithm per RFC 6238.
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49       Currently only OTP lengths of 6, 7 or 8 digits are supported.  This re‐
50       strictions may be lifted in future versions, although some  limitations
51       are inherent in the protocol.
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53       The flags parameter may be used to change the MAC function, for example
54       OATH_TOTP_HMAC_SHA256 or OATH_TOTP_HMAC_SHA512.
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RETURNS

57       Returns absolute value of position in OTP window (zero is  first  posi‐
58       tion), or OATH_INVALID_OTP if no OTP was found in OTP window, or an er‐
59       ror code.
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SINCE

62       2.6.0
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REPORTING BUGS

65       Report bugs  to  <oath-toolkit-help@nongnu.org>.   liboath  home  page:
66       https://www.nongnu.org/oath-toolkit/  General  help using GNU software:
67       http://www.gnu.org/gethelp/
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70       Copyright © 2009-2020 Simon Josefsson.
71       Copying and distribution of this file, with  or  without  modification,
72       are  permitted in any medium without royalty provided the copyright no‐
73       tice and this notice are preserved.
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77liboath                              2.6.9              oath_totp_validate4(3)
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