package civitas.crypto.parameters.encoder;
   
   import civitas.crypto.CryptoException;
   import civitas.crypto.parameters.ElGamalParameters;
   import civitas.util.CivitasBigInteger;
   
   public class SafePrimeDecode {
   	public CivitasBigInteger apply(CivitasBigInteger i, final ElGamalParameters elGamalParameters)
   			throws CryptoException {
  		if (i.compareTo(elGamalParameters.p) > 0) {
  			throw new CryptoException("Message is too large for parameters");
  		}
  		if (i.compareTo(elGamalParameters.q) > 0) {
  			i = elGamalParameters.p.subtract(i);
  		}
  		return i;
  	}
  }