com.jcraft.jsch

Interface KeyPairGenDSA

public interface KeyPairGenDSA

Usually not to be used by applications. A generator for a DSA key pair.

The library contains a default implementation of this class, based on the JCE classes available in Java SE from 1.4.

The actual implementation class is chosen by the configuration option "keypairgen.dsa", and then instantiated using the no-argument constructor. The library uses each instance only for one key generation.

This object will create a DSA key pair, consisting of a public key (p, q, g, y) and a private key x.

Here q is a 160-bit prime (when using SHA-1), p a prime of the given key size such that p-1 is a multiple of q, g is a generator of a multiplicative subgroup of order q of (Z/pZ)^*. p, q and g are called community parameters and can be shared by many keys (some implementations may have precalculated ones).

x is a random number with 0 < x < q, and y = g^x mod p - these two numbers are key pair specific, and x must be preserved secretely.

Method Summary

Modifier and Type	Method and Description
byte[]	getG() The generator g of the subgroup.
byte[]	getP() The modulus p, a prime.
byte[]	getQ() The order q of the subgroup of (Z/pZ)^* generated by g, also prime.
byte[]	getX() The secret key x.
byte[]	getY() The public key y = g^x mod p.
void	init(int key_size) Generates a key pair.

Method Detail

init

void init(int key_size)
   throws Exception

Generates a key pair. The other methods can then be called to retrieve the key components.

Parameters:

key_size - the number of bits of the key to be produced.

Throws:

Exception

getX

byte[] getX()

The secret key x.

getY

byte[] getY()

The public key y = g^x mod p.

getP

byte[] getP()

The modulus p, a prime.

getQ

byte[] getQ()

The order q of the subgroup of (Z/pZ)^* generated by g, also prime.

getG

byte[] getG()

The generator g of the subgroup.