You mean "Surrogate Currency," shadow sounds to cool for him to think of.   I don't think these old senators understand technology enough to realize that BitCoins and Silk Road really have nothing to do with each other.  If the fed was worried, then it would be taken on by a department by now and not discussed in this manner.  These morons are simply pandering to their constituency without full knowledge of what's what, which is normally a desperate attempt to feel relevant within government.