com.fasteasytrade.JRandTest.Algo
Class ModulusExponentPrng

java.lang.Object
  com.fasteasytrade.JRandTest.Algo.Cipher
      com.fasteasytrade.JRandTest.Algo.ModulusExponentPrng

public class ModulusExponentPrng

extends Cipher

ModulusExponent Prng algorithm from NIST test package

Fix random p, prime, length 512 bits.

Fix random g, prime, length 512 bits. g < p.

Fix random e, prime, length 160 bits.

Each prng iteration calculate g = g**e mod p.
The lowest 64 bits of g are the prng result.

Author:

Zur Aougav

Field Summary

int	bit_length p and g length/num of bits
(package private) BigInteger	e Initial e is a random prime (with probability < 2 ** -100) Length of e is e_bit_length = 160 bits = 20 bytes.
int	e_bit_length e length/num of bits
(package private) BigInteger	g Initial g is a random prime (with probability < 2 ** -100) Length of g is bit_length = 512 bits = 64 bytes.
(package private) BigInteger	g0 g0 is the "initial state" of the prng.
(package private) BigInteger	p prime (with probability < 2 ** -100).

Constructor Summary

(package private)	ModulusExponentPrng()
(package private)	ModulusExponentPrng(BigInteger p, BigInteger g, BigInteger e)
(package private)	ModulusExponentPrng(BigInteger p, BigInteger g, BigInteger e, BigInteger g0)
(package private)	ModulusExponentPrng(int x)

Method Summary

BigInteger	getE() Public key.
BigInteger	getG() Secret key
BigInteger	getP() Public key.
long	nextLong() calculate g**e mod p and returns lowest 64 bits, long.
void	reset() Reset "state" of prng by setting g to g0 (initial g).
(package private) void	setup(int len) Generate the keys and seed for Modulus Exponent Prng.

Methods inherited from class com.fasteasytrade.JRandTest.Algo.Cipher

compareBytes

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Field Detail

bit_length

public final int bit_length

p and g length/num of bits

See Also:

Constant Field Values

e_bit_length

public final int e_bit_length

e length/num of bits

See Also:

Constant Field Values

p

BigInteger p

prime (with probability < 2 ** -100).

Length of p is bit_length = 512 bits = 64 bytes.

g

BigInteger g

Initial g is a random prime (with probability < 2 ** -100)

Length of g is bit_length = 512 bits = 64 bytes.

g is the "state" of the prng.

g = take 64 lowr bits of ( g**3 mod n ).

e

BigInteger e

Initial e is a random prime (with probability < 2 ** -100)

Length of e is e_bit_length = 160 bits = 20 bytes.

e is the "exponent" of the prng.

g0

BigInteger g0

g0 is the "initial state" of the prng.

reset method set g to g0.

Constructor Detail

ModulusExponentPrng

ModulusExponentPrng()

ModulusExponentPrng

ModulusExponentPrng(int x)

ModulusExponentPrng

ModulusExponentPrng(BigInteger p,
                    BigInteger g,
                    BigInteger e)

ModulusExponentPrng

ModulusExponentPrng(BigInteger p,
                    BigInteger g,
                    BigInteger e,
                    BigInteger g0)

Method Detail

setup

void setup(int len)

Generate the keys and seed for Modulus Exponent Prng.

Select random primes - p, g. g < p.

Parameters:

len - length of p and g, num of bits.

nextLong

public long nextLong()

calculate g**e mod p and returns lowest 64 bits, long.

getP

public BigInteger getP()

Public key.

Returns:

p prime (with probability < 2 ** -100)

getE

public BigInteger getE()

Public key.

Returns:

e prime (with probability < 2 ** -100)

getG

public BigInteger getG()

Secret key

Returns:

g prime (with probability < 2 ** -100)

reset

public void reset()

Reset "state" of prng by setting g to g0 (initial g).