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, 4 insertions, 0 deletions

diff --git a/eccrypto.h b/eccrypto.h
index 716369a2..7fce9cfa 100644
--- a/eccrypto.h
+++ b/eccrypto.h
@@ -22,6 +22,8 @@
 #include "ecp.h"

 #include "ec2n.h"

 

+#include <iosfwd>

+

 #if CRYPTOPP_MSC_VERSION

 # pragma warning(push)

 # pragma warning(disable: 4231 4275)

@@ -168,6 +170,8 @@ protected:
 	mutable bool m_compress, m_encodeAsOID;		// presentation details

 };

 

+inline std::ostream& operator<<(std::ostream& os, const DL_GroupParameters_EC<ECP>::Element& obj);

+

 /// \brief Elliptic Curve Discrete Log (DL) public key

 /// \tparam EC elliptic curve field

 template <class EC>