An aroma like rotten eggs or burning matches is usually caused by certain strains of yeast during fermentation. It is sometimes caused by bacteria or yeast autolysis (yeast digesting itself).
Always watch your sanitation procedures throughout the process. Sulfuric aroma usually dissipates over time and is driven off by CO2 production and higher fermentation temperatures. Rack the beer off of the yeast sediment a few days after fermentation is complete to avoid yeast autolysis.