Greece's problem is not a currency problem, Euro is a pretty strong currency, one of the major world reserve currencies, Greece's problem is about debt, corruption and incompetent politicians.
There is a chance that they will be kicked out of the Euro Zone, if they refuse to honour the debt repayment deadlines. The Greek government is already discussing the emergency strategy in case such an incident actually happens (the probability for which is like 50-50 right now). But as far as I know, they are not considering to introduce a digital currency to replace the Euro. Some ministers want to re-introduce the Greek Drachma, while the others want to replace the Euro with Russian Ruble (which itself is a very risky option).