Implementations of the present invention provide systems, methods, and apparatus for stopping unauthorized transactions before they are processed, as well as for creating and using one or more sub-accounts. For example, a debit or credit account can be activated or deactivated at will through various...http://www.google.com/patents/US7954704?utm_source=gb-gplus-sharePatent US7954704 - Electronic payment system with PIN and sub-account configurations
