(c) 2021 Alexandre Janon
A small HOTP/TOTP SHA1 client written in C99, without dependencies.
Compile with make.
Usage:
./mini_totp_sha1 <base32 secret> [<interval=30>] [<digits=6>] [<UNIX timestamp=now>]
To use HOTP codes, set interval to 1 and UNIX timestamp to the HOTP counter.
Test with: (see RFC6238 Appendix B)
$ ./mini_totp_sha1 $(printf 12345678901234567890|base32) 30 8 59
94287082
For convenience we include a tiny and rough Simple Network Time Protocol (RFC4330) client which echoes UNIX timestamp given by server pool.ntp.org.
SNTP and TOTP are composed by the included shell script sntp_totp_sha1 :
$ ./sntp_totp_sha1 $(printf 12345678901234567890|base32) 30 8
95142869