look, says mathematician charles hoskinson, digital currencies are like any new technology. >> and just like the internet can be used for bad things, like terrorist activity or child pornography, bitcoin could be used for bad things, for example, funding rogue states like iran or north korea. >> reporter: or dealing drugs, or laundering money. yes, bitcoin as a currency did initially appeal mainly to outliers, admits kinnard hockenhull, but it has begun to go mainstream, especially with investors. >> they think this is skyrocketing, i better get into it. but you also have people who want to use it, to send money instantly over the internet. and with bitcoin you can send money the same way you send an email. >> it's money that's designed for the internet. >> reporter: stephen pair has co-founded bitpay, a bitcoin payment processor. >> if you think about credit cards, they were designed in the 1950s, before the internet existed, right, so this is the first time we've taken everything we know about cryptography and the internet and security and designed a new payment system from ground up.