Secure PHP random bytes
by @shoghicp

Useful for generating strong keys or random data. Better than default PHP random functions. Lots of different sources of entropy


Basic Usage: string randomBytes( [ int $length = 16 [, bool $secure = true [, bool $raw = true [, mixed $startEntropy = "" [, &$rounds [, &$drop ]]]]]])

	$length = 16;
	$bytes = randomBytes($length, true, false); //This will return 32 secure hexadecimal characters
	$bytes = randomBytes($length, false, true); //This will return 16 binary characters


	
Randomness tests using ENT (http://www.fourmilab.ch/random/)
	Machine: Windows 7 SP1 Intel i5 2.4 GHz x64 PHP 5.4.3, So no /dev/urandom
	
	USING SECURE MODE
	Generator code: randomBytes(524288, true, true, "", $rounds, $drop);
	Output:
		Entropy = 7.999653 bits per byte.

		Optimum compression would reduce the size
		of this 524288 byte file by 0 percent.

		Chi square distribution for 524288 samples is 252.21, and randomly
		would exceed this value 53.77 percent of the times.

		Arithmetic mean value of data bytes is 127.3803 (127.5 = random).
		Monte Carlo value for Pi is 3.144482210 (error 0.09 percent).
		Serial correlation coefficient is -0.002599 (totally uncorrelated = 0.0).
		
	USING NON-SECURE MODE
	Generator code: randomBytes(1048576, false, true, "", $rounds, $drop);
	Output:
		Entropy = 7.999840 bits per byte.

		Optimum compression would reduce the size
		of this 1048576 byte file by 0 percent.

		Chi square distribution for 1048576 samples is 232.65, and randomly
		would exceed this value 83.90 percent of the times.

		Arithmetic mean value of data bytes is 127.5482 (127.5 = random).
		Monte Carlo value for Pi is 3.139217908 (error 0.08 percent).
		Serial correlation coefficient is -0.002567 (totally uncorrelated = 0.0).
		
	
This program is free software: you can redistribute it and/or modify
it under the terms of the GNU Lesser General Public License as published by
the Free Software Foundation, either version 3 of the License, or
(at your option) any later version.

This program is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
GNU Lesser General Public License for more details.

You should have received a copy of the GNU Lesser General Public License
along with this program.  If not, see <http://www.gnu.org/licenses/>.