AnsweredAssumed Answered

Security Engine (PKEU) calculation

Question asked by Ducson Nguyen on May 5, 2007
Latest reply on Dec 2, 2008 by Miguel Angel Calleja
I am attempting to implement the Digital Signature Algorithm verification process using the PKEU's math functions. I can get every step of the verification to compute properly except what one would think is the easiest part: x mod q, where x is a 512-bit result of numerous calculations beforehand, and q is a 160-bit value.

I tried converting x and the number 1 into Montgomery form, and using MOD_MULT2_DECONV. This doesn't work. I've also tried padding q with leading zeroes so it is 512 bits long and that doesn't help.

Does anybody have a suggestions as to how to perform this simple calculation using the PKEU?

Thank you for any help.