"Change is the law of life." - John F. Kennedy 

A New Era, A New Law

A Security:

A Security is a tradable financial asset.

A Currency:

A Currency is money in any form when in actual use or circulation as a medium of exchange.

The SEC Solution

As the main problem lies in defining whether or not cryptocurrency is a Security or Currency, the SEC should create a new law called the Crypto-Security.

A Crypto-Security would define a cryptocurrency as both possessing the nature and behavior of a Security and Currency. 

It's quite simple when you think about it, right.