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.
This reverts commit eb3b27a6a5. The change broke GCC 4.8 and unknown version of Clang on OS X. UB reported the OS X break, and JW found duplicated the break on a ARM CubieTruck with GCC 4.8.
This should have happened when we removed most of MAINTAIN_BACKWARDS_COMPATIBILITY artifacts. Its not practical move SHA1 into Weak:: namespace or "typedef SHA256 SHA" because SHA1 is too intertwined at the moment.
In the interim, maybe we can place SHA1 in both CryptoPP:: and Weak:: namespaces. This will allow us to transition into Weak::SHA1 over time, and signal to users SHA1 should be avoided.
Since we switched to CRYPTOPP_ASSERT we don't have to worry about an accidental assert in production. We can now assert ValidateElement and ValidateGroup and let the code warn of potential problems during development.
This came about because ECGDSA inadvertently used GetGroupOrder() rather than GetSubgroupOrder(). The assert alerted to the problem area without the need for debugging
Also add missing validation functions to test.cpp. The test and functions were present, but only accessible with 'cryptest.ex v', where all the tests were run
The typedefs were only commented so folks could search for a missing symbol, like Crypto++ 4.0 PK_FixedLengthEncryptor or PK_FixedLengthDecryptor
This is a distinct change from CRYPTOPP_MAINTAIN_BACKWARDS_COMPATIBILITY_562
