Some speculation about the Gold E Shun K order of ABC

There is an inactive ABC Gold E shun K order in hand

Input 12-bit activation code after boot, random input multiple times, failed

It took some time to guess the working mode of K-order:

Known:

K can not be networked, after the factory, in addition to the opportunity to enter the activation code, can not obtain any information

K-Order interior with clock

K-Power is very small, unable to complete complex operation

A guess on how it works:

Each K-order has a unique number m

The bank uses the function f (m,u) to get the 12-bit activation Code n (U is a random number)

The K-order detects if M and n match, and if not, rejects the boot

When activated, K-order generates random number seed R based on M and N

Each time the payment is made, the K order invokes the internal clock, gets the current time t, and the payment amount is P

Then a six-bit pseudo-random number z is obtained based on the function f (r,t,p)

The bank knows M,n, can use the same method to calculate r, and then get Z, thus completing the authentication

Inference:

Activation code cannot be used on another K-order

K-Order internal clock needs to be accurate, at least within three years of the factory error can not exceed one minute

Perhaps the bank calculates all z-values in ± 1 minutes to reduce the likelihood of user input errors.

Some speculation about the Gold E Shun K order of ABC