A Lua wrapper for OpenBSD's arc4random.

Requirements

lua >= 5.1

Copying

Many of the files in this repository have been taken from OpenBSD's tree. You should consult individual file headers for specific licensing information. More broadly, everything here is compatible with the ISC license.

Installation

$ luarocks install arc4random

Usage

The library provides two methods, random and buf. random is intended to be a drop in replacement for math.random, so it handles three cases.

arc4.random() returns a random floating point number in the range [0,1). arc4.random( n ) and arc4.random( m, n ) return a random integer in the range [1,n] and [m,n] respectively. All three cases match the behavior of math.random so you can do math.random = arc4.random and everything will keep working.

arc4.buf( n ) returns a string of n random characters. It is suitable for generating private encryption keys and IVs.

Some example code:

local arc4 = require( "arc4random" )

print( arc4.random() )
print( arc4.random( 3 ) )
print( arc4.random( -5, 5 ) )

local str = arc4.buf( 16 )
str = str:gsub( "(.)", function( c )
	return ( "%02x" ):format( string.byte( c ) )
end )
print( str )