I give you an alternative view instead of answer to your question. Most of the black money exists because of money's fiat nature. Money is printed in large quantities. Counterfeits are added to the circulation. Banker/Politician/Bureaucracy nexus often takes cuts from the supply.
I think Bitcoin can fix this. Money with every transaction identifiable. Which can't be counterfeited. Can't be created out of thin air.
From where I see, it solves more problems (or other problems).
If some criminal elements run away with the money. Solution will be to dedicate huge amount of resources to find them and recover the money. Instead of creating new money, which is like tax on everyone else holding it.