is a utility for generating, verifying, and synchronizing one-time passwords
created using the HOTP/OATH algorithm defined by RFC 4226.
is the tokens binary secret key and is specified as a hexadecimal string.
generates the one-time password corresponding to the given key and target counter value
and prints to standard output the counter followed by the decimal and hexadecimal one-time passwords.
is given, then
is the correct one-time password for the given
and counter value.
If so, it outputs the counter value.
may be either the decimal or hexadecimal one-time password.
The target counter value is determined as follows: if the
flag is given, use the current time in seconds since the UNIX epoch divided by the configured time interval (default 30 seconds);
otherwise, if the
flag is given, use the given
otherwise, use the value zero.
In both cases, a range of target counter values may be specified using the
will search the entire range for a matching counter value,
starting with the target counter value and working away from it.
This mode can be used to resynchronize an unsychronized counter.