org.mozilla.jss.crypto

Class PQGParams

java.lang.Object

java.security.spec.DSAParameterSpec

org.mozilla.jss.crypto.PQGParams

All Implemented Interfaces:

java.security.interfaces.DSAParams, java.security.spec.AlgorithmParameterSpec

public class PQGParams
extends java.security.spec.DSAParameterSpec

PQG parameters for DSA key generation, along with the seed, counter, and H values for verification.

This class has two main purposes: generating PQG parameters and verifying PQG parameters. To generate PQG parameters, call one of the static generate methods. They will return a new set of PQG paramters. To verify existing PQG parameters, create a new PQGParams object with the constructor and call paramsAreValid on the object.

It is necessary to call CryptoManager.initialize before using this class.

Constructor Summary

Constructors

Constructor and Description
PQGParams(java.math.BigInteger P, java.math.BigInteger Q, java.math.BigInteger G, java.math.BigInteger seed, int counter, java.math.BigInteger H) Creates a PQGParams object from a set of pre-computed DSA parameters.

Method Summary

Methods

Modifier and Type	Method and Description
static byte[]	BigIntegerToUnsignedByteArray(java.math.BigInteger big) Produces an unsigned byte-array representation of a BigInteger.
static PQGParams	generate(int keySize) Generates P, Q, and G parameters for DSA key generation.
static PQGParams	generate(int keySize, int seedBytes) Generates P, Q, and G parameters for DSA key generation.
int	getCounter()
java.math.BigInteger	getH()
java.math.BigInteger	getSeed()
boolean	paramsAreValid() Verifies the PQG parameters using the seed, counter, and H values.

Methods inherited from class java.security.spec.DSAParameterSpec

getG, getP, getQ

Methods inherited from class java.lang.Object

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

Constructor Detail

PQGParams

public PQGParams(java.math.BigInteger P,
         java.math.BigInteger Q,
         java.math.BigInteger G,
         java.math.BigInteger seed,
         int counter,
         java.math.BigInteger H)

Creates a PQGParams object from a set of pre-computed DSA parameters.

Parameters:

P - The DSA prime parameter.

Q - The DSA sub-prime parameter.

G - The DSA base parameter.

seed - The Seed used to calculate P, Q, and G.

counter - The Counter (C) used to calculate P, Q, and G.

H - The H value used to generate P, Q, and G.

Method Detail

generate

public static PQGParams generate(int keySize)
                          throws java.security.InvalidParameterException,
                                 PQGParamGenException

Generates P, Q, and G parameters for DSA key generation. Also provides the seed, counter, and H values for verification of the P, Q, and G. The parameters are generated and then verified before being returned. The length of the Seed will equal the length of P. It is necessary to call one of the CryptoManager.initialize functions before calling this method.

Parameters:

keySize - The size of P in bits. Keys generated by these P, Q, and G values will have this length. Valid key sizes are multiples of 64 in the closed interval [512,1024]. This also dictates the length of H and Seed.

Returns:

A new set of P, Q, and G parameters, along with the Seed, Counter, and H values used to generate them.

Throws:

java.security.InvalidParameterException - If the keySize is outside the bounds described by the DSA key pair generation algorithm.

PQGParamGenException - If an error occurs during the generation process.

See Also:

CryptoManager.initialize(java.lang.String)

generate

public static PQGParams generate(int keySize,
                 int seedBytes)
                          throws java.security.InvalidParameterException,
                                 PQGParamGenException

Generates P, Q, and G parameters for DSA key generation. Also provides the seed, counter, and H values for verification of the P, Q, and G. The parameters are generated and then verified before being returned. It is necessary to call one of the CryptoManager.initialize functions before calling this method.

Parameters:

keySize - The size of P in bits. Keys generated by these P, Q, and G values will have this length. Valid key sizes are multiples of 64 in the closed interval [512,1024]. This also dictates the length of H.

seedBytes - The number of bytes in the Seed value used to generate P, Q, and G. seedBytes must be from the closed interval [20,255].

Returns:

A new set of P, Q, and G parameters, along with the Seed, Counter, and H values used to generate them.

Throws:

java.security.InvalidParameterException - If the keySize or number of seed bytes is outside the bounds described by the DSA key pair generation algorithm.

PQGParamGenException - If an error occurs during the generation process.

See Also:

CryptoManager.initialize(java.lang.String)

BigIntegerToUnsignedByteArray

public static byte[] BigIntegerToUnsignedByteArray(java.math.BigInteger big)

Produces an unsigned byte-array representation of a BigInteger.

BigInteger adds an extra sign bit to the beginning of its byte array representation. In some cases this will cause the size of the byte array to increase, which may be unacceptable for some applications. This function returns a minimal byte array representing the BigInteger without extra sign bits.

Returns:

An unsigned, big-endian byte array representation of a BigInteger.

paramsAreValid

public boolean paramsAreValid()

Verifies the PQG parameters using the seed, counter, and H values.

Returns:

true if the parameters verified correctly, false if they did not verify.

getSeed

public java.math.BigInteger getSeed()

Returns:

The Seed used to generate P, Q, and G.

getCounter

public int getCounter()

Returns:

The Counter (C) used to generate P, Q, and G.

getH

public java.math.BigInteger getH()

Returns:

The H value used to generate P, Q, and G.