Question: DO IN ASSEMMBLY A common operation in cryptography is to compute c = x e , where e is a constant. A typical choice for

DO IN ASSEMMBLY A common operation in cryptography is to compute c=xe, where e is a constant. A typical choice for e is
the value 65537=216+1 because there exists a fast assembly routine for this value using a technique called
repeated squaring.
Repeated squaring can be used to quickly calculate exponents that are a power of two. For example, x4 can
be computed as (x2)2 using two imul q instructions. Similarly, x216 can be computed using sixteen imul q
instructions.
The routine works like this:
Save x in a temporary variable (such as a register).
Compute y=x216 using repeated squaring and store y in another temporary variable (such as another
register).
Return z=x*y, which is x65537 because x*x216=x216+1 by the laws of exponents.
Implement this fast exponentiation routine in x86-64 assembly. You must use a loop for the repeated squar-
ing, properly align memory, follow x86-64 register conventions, and provide a comment for each assembly
instruction.
You should use assume that e=65537 is a constant and imulq instructions will not overflow. ?1 The only
parameter will be x. You do not have to implement any test cases.
An example function prototype in C for your implementation is as follows:
// Compute x-65537
int64_t fast_exponentiate (int64_t x);
Some example calls:
fast_exponentiate (0)
fast_exponentiate(2)
fast_exponentiate(17)
 DO IN ASSEMMBLY A common operation in cryptography is to compute

Step by Step Solution

There are 3 Steps involved in it

1 Expert Approved Answer
Step: 1 Unlock blur-text-image
Question Has Been Solved by an Expert!

Get step-by-step solutions from verified subject matter experts

Step: 2 Unlock
Step: 3 Unlock

Students Have Also Explored These Related Databases Questions!