Pseudorandom Generator (PRG)

A pseudorandom generator (PRG) is a deterministic algorithm that takes a “short” uniformly distributed string, known as the seed, and outputs a longer string that cannot be efficiently distinguished from a uniformly distributed string of that length.

The PseudorandomGenerator Interface

public void getPRGBytes(byte[] outBytes, int outOffset, int outlen)

Streams the prg bytes.

Parameters:

• outBytes – output bytes. The result of streaming the bytes.
• outOffset – output offset
• outlen – the required output length

Basic Usage

//Create secret key and out byte array
...

//Create prg using the PrgFactory
PseudorandomGenerator prg = PrgFactory.getInstance().getObject("RC4");
SecretKey secretKey = prg.generateKey(256); //256 is the key size in bits.

//set the key
Prg.setKey(secretKey);

//get PRG bytes. The caller is responsible for allocating the out array.
//The result will be put in the out array.
prg.getPRGBytes(out.length, out);