DORDRECHT, Netherlands, Nov 23 (Reuters) - In the eight years he ran an online market selling images of violent child sexual abuse, Michael Mohammad made the equivalent of more than 100,000 euros. At his trial in May, while some of his victims listened, he told the judge: "It was purely business." The Dutch court sentenced Mohammad to 10 years in jail after convicting him of a litany of crimes. They included distributing thousands of photos and videos of child abuse, rape and bestiality via his website, Dark Scandals. He forced a dozen girls under the age of 16 to penetrate themselves and record it. He raped two of them and filmed it. A new breed of company enabled his business: cryptocurrency exchanges. Mohammad's customers used these platforms to buy digital tokens with dollars and euros, and spend them with relative anonymity. These tokens were the currency of Mohammad's abuse. In all, transaction data reviewed by Reuters show, Dark Scandals' customers used alm...