package civitas.crypto.decriptionshare;
   
   import org.springframework.beans.factory.annotation.Autowired;
   import org.springframework.stereotype.Controller;
   
   import civitas.crypto.ciphertext.ElGamalCiphertext;
   import civitas.crypto.parameters.ElGamalParameters;
   import civitas.crypto.proofdisclog.VerifyElGamalProofDiscLogEquality;
   import civitas.crypto.publickey.ElGamalPublicKey;
  
  @Controller
  public class VerifyElGamalDecryptionShare {
  
  	@Autowired
  	public VerifyElGamalProofDiscLogEquality verifyElGamalProofDiscLogEquality;
  
  	public boolean apply(final ElGamalDecryptionShare that, final ElGamalCiphertext c, final ElGamalPublicKey key)
  			throws Error {
  		if (c == null) {
  			throw new IllegalArgumentException("null ciphertext");
  		}
  		if (key == null) {
  			throw new IllegalArgumentException("null key");
  		}
  		ElGamalParameters params = key.params;
  		if (that.proof().g1().equals(c.a)
  				&& that.proof().g2().equals(params.g)
  				&& that.proof().v().equals(that.ai())
  				&& that.proof().w().equals(key.y)) {
  			return verifyElGamalProofDiscLogEquality.apply(that.proof(), params);
  		}
  
  		return false;
  	}
  }