public File askForTargetArchive(File def) {
        JFileChooser chooser = new JFileChooser();
        chooser.setFileFilter(new FileFilter() {
                public boolean accept(File f) {
                    if(f.isDirectory())
                        return true;
                    else{
                        Algorithm algs[] = model.getAlgorithms();
                        for(int i = 0; i < algs.length; i++){
                            if(f.getName().endsWith(algs[i].getSuffix())){
                                return true;
                            }
                        }
                        return false;
                    }
                }
                public String getDescription() {
                    return "jFileCrypt-Archive";
                }
            });
        chooser.setSelectedFile(def);
        int returnVal = chooser.showSaveDialog(view);
        if(returnVal == JFileChooser.APPROVE_OPTION) {
           return chooser.getSelectedFile();
        } else {
            return null;
        }
    }