2 -- Copyright (C) 2008-2010 Matthew Wild
3 -- Copyright (C) 2008-2010 Waqas Hussain
5 -- This project is MIT/X11 licensed. Please see the
6 -- COPYING file in the source package for more information.
10 local round_up = math.ceil;
11 local urandom, urandom_err = io.open("/dev/urandom", "r");
15 local function get_nibbles(n)
16 local binary_random = urandom:read(round_up(n/2));
17 local hex_random = binary_random:gsub(".",
18 function (x) return ("%02x"):format(x:byte()) end);
19 return hex_random:sub(1, n);
21 local function get_twobits()
22 return ("%x"):format(urandom:read(1):byte() % 4 + 8);
27 error("Unable to obtain a secure random number generator, please see https://prosody.im/doc/random ("..urandom_err..")");
29 -- generate RFC 4122 complaint UUIDs (version 4 - random)
30 return get_nibbles(8).."-"..get_nibbles(4).."-4"..get_nibbles(3).."-"..(get_twobits())..get_nibbles(3).."-"..get_nibbles(12);