Encryption Sample Data Problem
Original Post: security (SIG Forum ) Date: 2000-11-14
Question:
In page no. 902 of the Bluetooth specifications(Encryption Sample
Data):
It is given that for generating kc' from kc g1,g2 (for l=2) the kc
mod g1 value is given as 1ff0 but i am getting 09c54. Is there a problem with the modulus
operation?.
Answer:
All the operations must be over GF(2^128) and not over the ring of
integers Z_m, i.e., when multiplying or dividing, instead of using the normal arithmetic
addition/subtraction, just use xor (faster and simpler). Unfortunately this does not seem
to have been mentioned in earlier versions of the Bluetooth specs
|
