The legal challenges of E-cash entail concerns over taxes and currency issuers. In addition, consumer liability from bank cards will also have to be addressed (currently $50 for credit cards). E-cash removes the intermediary from currency transactions, but this also removes much of the regulation of the currency in the current system.
Tax questions immediately arise as to how to prevent tax evasion at the income or consumption level. If cash-like transactions become easier and less costly, monitoring this potential underground economy may be extremely difficult, if not impossible, for the IRS.
The more daunting legal problem is controling a potential explosion of private currencies. Large institutions that are handling many transactions may issue electronic money in their own currency. The currency would not be backed by the full faith of the United States, but by the full faith of the institution. This is not a problem with paper currency, but until the legal system catches up with the digital world, it may present a problem with cybercash.