Online Banking Security

[ck1]

I've got a little device from HSBC which generates a seemingly random 6 digit code when a button is pressed, the number has to be used for logging on to my online bank account, if the number matches that displayed on the fob it lets you in. How does the communication work between the security fob and the online bank system, it's not wifi connected...

[Old_Geezer]

Has to have some kind of wireless link, unless it's timed to change in a particular way at regular times.

Maybe you can check frequency allocations in the UK, see if the banks have any ?

[Mamyalynne]

http://uk.answers.yahoo.com/question/index?qid=20110609074405AAsMxrC

[Zacs-Master]

It is a very simple device that generates random looking number. However, it is not really random at all if you know the formula and only the 'creator' knows the number. The device has a clock that changes to the next number at known time intervals. If you didn't type the number in fast enough, the website would deny access expecting the next number.
this is related to encryption and authentication.
The bank site gives you a different number every time. This is done with the help of a random number generator which will give you always a different and a random number so that no one can guess it.
You enter this in your security device given by bank along with your pin code. This will be encrypted and another number will be given as output.
When you enter this number generated by bank security device, the bank's server also calculates this to see if you have entered a correct number.

[gingejbee]

There is no link between the two....

[tonyav]

I also have one of those for my HSBC online banking, good isn't it ck 1.

[gingejbee]

...only six digits? Usually eight, isn't it?

[tonyav]

6 digits on mine, gingejbee.

[gingejbee]

Oh, Barclays and Nationwide units generate two lots of four digits!

[Old_Geezer]

If you are entering a number from the website, then that is the link. If not then again it may well be a set sequence of changes, pseudo random or otherwise.