package civitas.crypto.proofknowndisclog;
   
   import org.springframework.stereotype.Controller;
   
   import civitas.crypto.parameters.ElGamalParameters;
   import civitas.util.CivitasBigInteger;
   
   @Controller
   public class VerifyElGamalProofKnowDiscLog {
  	public boolean apply(final ElGamalProofKnowDiscLog that, final ElGamalParameters params) {
  		try {
  			CivitasBigInteger u = params.g.modPow(that.r(), params.p);
  			CivitasBigInteger w = that.a().modMultiply(that.v().modPow(that.c(), params.p), params.p);
  
  			return u.equals(w);
  		} catch (NullPointerException | ArithmeticException e) {
  			return false;
  		}
  	}
  }