org.mozilla.jss.crypto

Class PQGParams

public class PQGParams extends 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
PQGParams(BigInteger P, BigInteger Q, BigInteger G, BigInteger seed, int counter, BigInteger H)
Creates a PQGParams object from a set of pre-computed DSA parameters.
Method Summary
static byte[]BigIntegerToUnsignedByteArray(BigInteger big)
Produces an unsigned byte-array representation of a BigInteger.
static PQGParamsgenerate(int keySize)
Generates P, Q, and G parameters for DSA key generation.
static PQGParamsgenerate(int keySize, int seedBytes)
Generates P, Q, and G parameters for DSA key generation.
intgetCounter()
BigIntegergetH()
BigIntegergetSeed()
booleanparamsAreValid()
Verifies the PQG parameters using the seed, counter, and H values.

Constructor Detail

PQGParams

public PQGParams(BigInteger P, BigInteger Q, BigInteger G, BigInteger seed, int counter, 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

BigIntegerToUnsignedByteArray

public static byte[] BigIntegerToUnsignedByteArray(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.

generate

public static PQGParams generate(int keySize)
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. org.mozilla.jss.crypto.PQGParamGenException If an error occurs during the generation process.

See Also: CryptoManager

generate

public static PQGParams generate(int keySize, int seedBytes)
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. org.mozilla.jss.crypto.PQGParamGenException If an error occurs during the generation process.

See Also: CryptoManager

getCounter

public int getCounter()

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

getH

public BigInteger getH()

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

getSeed

public BigInteger getSeed()

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

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.