This picks up about 0.2 cpb in ChaCha::OperateKeystream. It may not sound like much but it puts SSE2 intrinsics version on par with the ASM version of Salsa20. Salsa20 leads ChaCha by 0.1 to 0.15 cpb, which equates to about 50 MB/s.
Thanks to Jack Lloyd and Botan for allowing us to use the implementation.
The numbers for SSE2 are very good. When compared with Salsa20 ASM the results are:
* Salsa20 2.55 cpb; ChaCha/20 2.90 cpb
* Salsa20/12 1.61 cpb; ChaCha/12 1.90 cpb
* Salsa20/8 1.34 cpb; ChaCha/8 1.5 cpb
These changes made it in by accident at Commit b74a6f4445. We were going to try to let them ride but they broke versioning. They may be added later but we should avoid the change at this time.
Currently the CRYPTOPP_BOOL_XXX macros set the macro value to 0 or 1. If we remove setting the 0 value (the #else part of the expression), then the self tests speed up by about 0.3 seconds. I can't explain it, but I have observed it repeatedly.
This check-in prepares for the removal in Upstream master
trap.h and CRYPTOPP_ASSERT has existed for over a year in Master. We deferred on the cut-over waiting for a minor version bump (5.7). We have to use it now due to CVE-2016-7420
Jeffrey Walton