When given any number that is equal to 3 mod 4, mpp_pprime says
that number is prime.
The bug is simply that "res" is not set to MP_NO prior to the
for (jx = 1; jx < b; jx++)
loop, and if that loop executes zero times (because b is 1),
the result is MP_OK, not MP_NO.
Also, HoAC suggests using sequential values of a, rather than
random values of a.
mpp_pprime is the Miller Rabin pseudo-primality test.
I will check in a fix shortly.
I'm also going to do some other cleanup to the code.
I believe this bug is fixed in revision 1.13 of mpprime.c.
It passes the new test case I added to mpi-test
Changed target milestone to show this bug was fixed in NSS 3.1.1