Of course, it's quite likely that you either don't believe in the Bible or that you interpret in any of various ways which don't place a great deal of importance on that particular matter. But let's have a look at Ye Aulde Revelation anyway. From the King James Version ('cause that's how I roll scripture-wise), chapter 13, verses 16-17:
16 And he causeth all, both small and great, rich and poor, free and bond, to receive a mark in their right hand, or in their foreheads:
17 And that no man might buy or sell, save he that had the mark, or the name of the beast, or the number of his name.
The technology is definitely there. Think about it:
You have a cryptocurrency account. The identifier for that account is tattooed (perhaps as a QR code?) or microchipped on your right hand or forehead.
To give you money, all anyone has to do is scan the code and transfer money from their account to yours.
For you to spend money, you wave the QR code over a scanner and then enter a passphrase or use biometric identification or whatever to authorize a transfer out of the account and into another. Badabing, badaboom.
No reason this couldn't be done right now. Of course, the third element Mark-of-the-Beast-wise is that it's compulsory. Which, as we know, could never happen, because countries don't have legal tender laws or anything like that, right?
And no, I'm not trying to slam Bitcoin specifically or cryptocurrencies in general. I love'em (tip jar in the right sidebar, ladies and gents). But I still think it's interesting how something written circa 2,000 years ago features a hook on which the concept hangs so prettily.