http://www.bouncycastle.org/java.html: The Bouncy Castle Crypto package is a Java implementation of cryptographic algorithms. This jar contains JCE provider and lightweight API for the Bouncy Castle Cryptography APIs for JDK 1.5 to JDK 1.8.
  • The Legion of the Bouncy Castle Inc. 
package org.bouncycastle.crypto;

import java.math.BigInteger;


An "extended" interface for classes implementing DSA-style algorithms, that provides access to
the group order.

/**
 * An "extended" interface for classes implementing DSA-style algorithms, that provides access to
 * the group order.
 */
public interface DSAExt
    extends DSA
{
    
Get the order of the group that the r, s values in signatures belong to.

/**
     * Get the order of the group that the r, s values in signatures belong to.
     */
    public BigInteger getOrder();
}