randomword(3) Library Functions Manual randomword(3)
NAME
randomword, randomchars, randomletters - Generate random passwords (Enhanced Security)
LIBRARY
Security Library - libsecurity.so
SYNOPSIS
int randomchars( char *string, unsigned short int minlen, unsigned short int maxlen, boolean restrict, long seed);
int randomletters( char *string, unsigned short int minlen, unsigned short int maxlen, boolean restrict, long
seed);
int randomword( char *word, char *hyphenated_word, unsigned short int minlen, unsigned short int maxlen, boolean
restrict, long seed);
PARAMETERS
Points at a user-supplied space to contain a null-terminated password. Specifies the minimum length that a generated word can have. Spec-
ifies the maximum length that a generated word can have. Specifies whether restrictions are to be imposed on the generated word. This is
a boolean integer, where a non-zero integer indications restrictions and a 0 (zero) indicates no restrictions. Specifies an initial seed
for the random number generator. Points at a user-supplied space to contain a null-terminated random pronounceable password. Contains the
hyphenated version of the generated word.
DESCRIPTION
These functions generate random passwords for use in password selection. All of them are generated by the system, based on seeds and set
in the function. Such seeds can be created with the drand48(), rand(), or random() functions.
The randomchars() function places a null-terminated password composed of random printable ASCII characters into the string parameter and
returns the length of the generated string. The minlen parameter can equal maxlen, but cannot be greater than maxlen, and cannot be nega-
tive. The user space preallocated is at least maxlen for string. The smaller minlen and maxlen are, the smaller the selection space of
random words.
The restrict parameter is 0 (zero) when no restrictions are placed on the generated word. It is nonzero when the words generated pass the
tests of the acceptable_password() function.
The seed parameter is used by the function only on the first time it is called; the parameter is ignored on subsequent calls.
The randomletters() function places a null-terminated password composed of random lower-case letters into the string parameter and returns
the length of the generated word. The minlen, maxlen, restrict, and seed parameters are the same as for the randomchars() function.
The randomword() function places a null-terminated random pronounceable password into the word parameter and returns the length of the gen-
erated word. The minlen, maxlen, restrict, and seed parameters are the same as for the randomchars() and randomletters() functions. The
user space preallocated is at least 2*max - 1 for hyphenated_word.
NOTES
The password generator relies on a random number generator that produces uniformly distributed integers. Because the password generator
invokes the random number generator many times even for one word, the random number generator has to produce a uniform distribution. The
period (distinct numbers produced given a particular seed) and number space (range of possible numbers) must both be large. The drand48()
functions are used for this purpose.
Programs using these functions must be compiled with -lsecurity.
FILES
System password file. System group file.
RELATED INFORMATION
Functions: acceptable_password(3), drand48(3), rand(3), random(3).
Commands: login(1), passwd(1). delim off
randomword(3)