com.fasteasytrade.JRandTest.Algo
Class MicaliSchnorrPrng

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

public class MicaliSchnorrPrng

extends Cipher

Micali-Schnorr Prng algorithm.

Implements algorithm directly from public published book.

The following program implements and tests the Micali-Schnorr random bits generator. The test suite is according to FIPS 140-1. See "Handbook of Applied Cryptography" by Alfred J. Menezes et al Section 5.4.4 pages 181 - 183 and 5.37 Algorithm page 186.

Author:

Zur Aougav

Field Summary

(package private) int	bit_length n's length/num of bits
(package private) BigInteger	e e is a random exponent we calculate on generation (in setup method)
(package private) int	k nLength = r + k k is the number of low bits we will use in the prng
(package private) BigInteger	n n = p * q, and calculations are done mod n.
(package private) int	nLength nLength is length of n
(package private) BigInteger	p prime (with probability < 2 ** -100)
(package private) BigInteger	q prime (with probability < 2 ** -100)
(package private) int	r nLength = r + k r is the number of high bits we will use in the prng
(package private) BigInteger	x x is the "state" of the prng.
(package private) BigInteger	x0 x0 is the "initial state" of the prng.

Constructor Summary

(package private)	MicaliSchnorrPrng()
(package private)	MicaliSchnorrPrng(BigInteger n, BigInteger p, BigInteger q)
(package private)	MicaliSchnorrPrng(BigInteger n, BigInteger p, BigInteger q, BigInteger x)
(package private)	MicaliSchnorrPrng(int x)

Method Summary

BigInteger	getE()
int	getK()
BigInteger	getN() Public key.
void	getNextBits(byte[] result) calculate x**e mod n and returns lowest k bits, k/8 bytes, in result buffer.
int	getNLength()
BigInteger	getP() Secret key.
BigInteger	getQ() Secret key (need only one of p or q).
int	getR()
BigInteger	getX() Encryption: you need to get last x and write it to cipher output stream.
void	reset() Reset "state" of prng by setting x to x0 (initial x).
(package private) boolean	setup(int l) Generate the key and seed for Micali Schnorr 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

final int bit_length

n's length/num of bits

See Also:

Constant Field Values

n

BigInteger n

n = p * q, and calculations are done mod n.

p

BigInteger p

prime (with probability < 2 ** -100)

q

BigInteger q

prime (with probability < 2 ** -100)

x

BigInteger x

x is the "state" of the prng.

x = take r high bits of ( x**e mod n ).

returns k random bits from k low bits of ( x**e mod n ).

x0

BigInteger x0

x0 is the "initial state" of the prng.

reset method set x to x0.

e

BigInteger e

e is a random exponent we calculate on generation (in setup method)

nLength

int nLength

nLength is length of n

k

int k

nLength = r + k

k is the number of low bits we will use in the prng

r

int r

nLength = r + k

r is the number of high bits we will use in the prng

Constructor Detail

MicaliSchnorrPrng

MicaliSchnorrPrng()

MicaliSchnorrPrng

MicaliSchnorrPrng(int x)

MicaliSchnorrPrng

MicaliSchnorrPrng(BigInteger n,
                  BigInteger p,
                  BigInteger q)

MicaliSchnorrPrng

MicaliSchnorrPrng(BigInteger n,
                  BigInteger p,
                  BigInteger q,
                  BigInteger x)

Method Detail

setup

boolean setup(int l)

Generate the key and seed for Micali Schnorr Prng.

Select random p, q, n=p*q, x (mod n).

Parameters:

l - length of n, num of bits.

getNextBits

public void getNextBits(byte[] result)

calculate x**e mod n and returns lowest k bits, k/8 bytes, in result buffer.

getP

public BigInteger getP()

Secret key.

Returns:

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

getQ

public BigInteger getQ()

Secret key (need only one of p or q).

Returns:

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

getN

public BigInteger getN()

Public key.

Returns:

n = p * q

getE

public BigInteger getE()

Returns:

random exponent e

getX

public BigInteger getX()

Encryption: you need to get last x and write it to cipher output stream.

Decryption: you need to read "last x" from input stream, and calculate X0, the first x based on n (public key), p and q (secret key/keys).

Returns:

current x

getNLength

public int getNLength()

Returns:

length of n

getK

public int getK()

Returns:

k

getR

public int getR()

Returns:

r

reset

public void reset()

Reset "state" of prng by setting x to x0 (initial x).