Fix ECP leakage in Add() and Double() (GH #869, PR #871)

This check-in provides the fix for leaks in ECP's Add() and Double(). The fixes were taken from Joost Renes, Craig Costello, and Lejla Batina's [Complete addition formulas for prime order elliptic curves](https://eprint.iacr.org/2015/1060.pdf).

The Pull Request includes two additional changes that were related to testing the primary fix. First, an `AuthenticatedKeyAgreementWithRolesValidate` interface was added. It allows us to test key agreement when roles are involved. Roles are "client", "server", "initiator", "recipient", etc.

Second, `SetGlobalSeed` was added to `test.cpp` to help with reproducible results. We had code in two different places that set the seed value for the random number generator. But it was sloppy and doing a poor job since results could not be reproduced under some circumstances.

1 files changed, 0 insertions, 1 deletions

diff --git a/ec2n.h b/ec2n.h
index 6806444b..48e9fa28 100644
--- a/ec2n.h
+++ b/ec2n.h
@@ -3,7 +3,6 @@
 /// \file ec2n.h

 /// \brief Classes for Elliptic Curves over binary fields

 

-

 #ifndef CRYPTOPP_EC2N_H

 #define CRYPTOPP_EC2N_H