I've seen many approaches for strong authentication - most of them are either too expensive, too complicated, or they aren't really appealing. The latter is true for approaches like "passfaces" have to pick one or some known faces from different pictures. Many approaches are complicated to deliver. And many of the token-based approaches are complex from a logistics perspective and are expensive. However, many of these approaches and especially combinations of for example hardware tokens and soft-tokens will work for many use cases.

But there are other approaches which are interesting as well. One which looks pretty interesting is GrIDsure, provided by an UK vendor and implemented by several OEMs right now. The idea is to provide a grid of numbers and to define a pattern within this grid per user. One user might decide on picking the numbers in the corners, clockwise. The next one might pick numbers from the second line from the right to the left. Even a relatively small grid allows for many different combinations. And due to the fact that the numbers within the grid change every time, there is a very high number of changing PINs which then can be entered. The concept is easy to understand, doesn't require additional hardware and works with any type of device with a display.

Despite being really reluctant when a new vendor appears and likes to tell me that he has found the solution for strong authentication, the conversation with GrIDsure was definitely interesting. At least interesting enough to cover it in my blog and to do further research on that solution.