passlen(S)                     6 January 1993                     passlen(S)


 Name

    passlen - determine minimum password length of an account

 Syntax


    cc  . . .  -lprot -lm


    #include <sys/types.h>
    #include <sys/security.h>
    #include <sys/audit.h>
    #include <prot.h>

    int passlen (life_dur, login_delay, alphabet_size)
    time_t life_dur;
    time_t login_delay;
    int alphabet_size;


 Description

    The passlen routine returns the minimum password length according to the
    algorithm in the DoD Password Management Guideline (Green Book) given the
    password lifetime duration for an account in seconds, the argument
    lifedur; the login delay between login attempts in seconds, the argument
    logindelay; and the alphabetsize of distinct characters. Two of the pa-
    rameters used by the Guideline are fixed, namely the size of the alphabet
    at 26 characters (the argument alphabetsize should always reflect this)
    and the probability of guessing a password at 1 chance in a million.


 Return value

    The passlen routine returns the result of the calculation rounded up to
    the nearest integer so as to err on the side of greater security.
    passlen is always successful and therefore no errors are defined.

 Note

    If the lifetime duration, the login delay time, or the guess parameter
    changes in the Protected Password database for this account (or for the
    system default if those values are used in an account), it is a good idea
    to invalidate the password in case the new parameters require a longer
    minimum password length.

 See also

    exp(S), floor(S), passwd(C), randomword(S)
    DoD Password Management Guideline (Green Book),
    CSC-STD-002-85, 12 April 1985.

 Standards conformance

    The passlen routine is an extension of AT&T System V provided by the
    Santa Cruz Operation.