An EDI format for monetary transactions prevents a perpetual fee. EDI formats are free.
Bitcoin uses an algorithm designed by the NSA. Is there a back door on that algorithm? I do not know. However, knowing the people involved, I suspect there is. While Bitcoin (and other digital currencies) reduce the fees, it is not perfect. So, how to prevent a perpetual fee?
All transactions can be described as:
Time stamps on each stage clarify risk and accountability.
That is "Promise Language" - a simple EDI format to describe all transactions, regardless of currency. For free.