1 .TH GENRANDOM 3
2 .SH NAME
3 genrandom, prng \- random number generation
4 .SH SYNOPSIS
5 .B #include <u.h>
6 .br
7 .B #include <libc.h>
8 .br
9 .B #include <mp.h>
10 .br
11 .B #include <libsec.h>
12 .PP
13 .B
14 void	genrandom(uchar *buf, int nbytes)
15 .PP
16 .B
17 void	prng(uchar *buf, int nbytes)
18 .SH DESCRIPTION
19 .PP
20 Most security software requires a source of random or, at the
21 very least, unguessable numbers.
22 .PP
23 .I Genrandom
24 fills a buffer with bytes from the X9.17 pseudo-random
25 number generator.  The X9.17 generator is seeded by 24
26 truly random bytes read from
27 .BR /dev/random .
28 .PP
29 .I Prng
30 uses the native
31 .IR rand (3)
32 pseudo-random number generator to fill the buffer.  Used with
33 .IR srand ,
34 this function can produce a reproducible stream of pseudo random
35 numbers useful in testing.
36 .PP
37 Both functions may be passed to
38 .I mprand
39 (see
40 .IR mp (3)).
41 .SH SOURCE
42 .B /usr/local/plan9/src/libsec
43 .SH SEE ALSO
44 .IR mp (3)