Java tutorial
import java.math.BigInteger; import java.security.KeyFactory; import java.security.KeyPair; import java.security.KeyPairGenerator; import java.security.PrivateKey; import java.security.Signature; import java.security.interfaces.DSAParams; import java.security.interfaces.DSAPrivateKey; import java.security.interfaces.DSAPublicKey; import java.security.spec.DSAPrivateKeySpec; import java.security.spec.KeySpec; public class Main { public static void main(String[] argv) throws Exception { KeyPairGenerator keyGen = KeyPairGenerator.getInstance("DSA"); keyGen.initialize(1024); KeyPair keypair = keyGen.genKeyPair(); DSAPrivateKey privateKey = (DSAPrivateKey) keypair.getPrivate(); DSAPublicKey publicKey = (DSAPublicKey) keypair.getPublic(); DSAParams dsaParams = privateKey.getParams(); BigInteger p = dsaParams.getP(); BigInteger q = dsaParams.getQ(); BigInteger g = dsaParams.getG(); BigInteger x = privateKey.getX(); BigInteger y = publicKey.getY(); // Create the DSA key factory KeyFactory keyFactory = KeyFactory.getInstance("DSA"); // Create the DSA private key KeySpec privateKeySpec = new DSAPrivateKeySpec(x, p, q, g); PrivateKey privateKey1 = keyFactory.generatePrivate(privateKeySpec); byte[] buffer = new byte[1024]; Signature sig = Signature.getInstance(privateKey1.getAlgorithm()); sig.initSign(privateKey1); sig.update(buffer, 0, buffer.length); } }