acceptable_password(3)					     Library Functions Manual					    acceptable_password(3)

NAME

       acceptable_password - Determines if a password meets deduction requirements (Enhanced Security)

LIBRARY

       Security Library - libsecurity.so

SYNOPSIS

       int acceptable_password(      char *word,      FILE *stream);

PARAMETERS

       Points to the suggested password.  Points to the stream to write diagnostics into.

DESCRIPTION

       The  acceptable_password()  function determines if the given password is difficult to deduce from well known, password-guessing heuristics.
       The cleartext (plaintext) password is passed as the first argument, and the file pointer of the stream that is used to report failure  rea-
       sons is the second argument.  If this checking is to be silent, the second argument should be a null file pointer.

       When the acceptable_password() function returns a value of 1, the password provided meets all the tests listed in the following text.  When
       it returns a value of 0 (zero), the password failed to meet at least one of the tests.

       The selectivity criteria for the password include but cannot be limited to the following four tests: This test passes if the word is not  a
       palindrome.   (A  palindrome  is a word that is spelled the same backwards as it is forwards.)  Examples of palindromes that fail this test
       are mom, dad, noon, redivider, radar.  Palindromes do not make good passwords because they reduce an n character password to n/2 + 1  char-
       acters.	 A  penetrator	knowing  that palindromes were legal could use heuristics that could deduce the password much more quickly than if
       they were excluded.  This test passes if the password is not a derivative of a login name for the  system.   Many  insecure  systems  allow
       passwords  to be the login name itself.	This is a fact known by many penetrators.  All login names are excluded because a user that is the
       owner of several pseudouser accounts can elect to use the login name of one account as the password for all accounts.  Similar to the login
       name  issue,  this  test  passes if the password is not a group name derivative.  This test passes if the spell program determines that the
       password is not an English word.  A penetrator then could not search the online dictionary to find the password.  The  spell  program  also
       has  some built-in rules that go beyond the actual online dictionary in determining what is a proper word, and this routine takes advantage
       of that.

NOTES

       Programs that use this routine must be compiled with -lsecurity.

FILES

       System password file.  System group file.

RELATED INFORMATION

       Functions: getpwent(3), getgrent(3).

       Commands: spell(1).  delim off

															    acceptable_password(3)