Hey Jeff, thanks for the fast response! Yes, the encrypted sha from your AMD CPUs matches what I get on my Ryzen 7 3700X.
The encrypted sha from the i7 is 8F16077454F8477594CAD4304126B0A6F30C8C4D2536E2441FFFD320656E1DF1. That's also the sha I get if I disable AVX on my Ryzen when compiling cryptopp. I'm not sure which sha is "correct" but we are seeing the same behavior across the AMD CPUs. Would it make sense to disable assembly altogether to get a reference encrypted sha256? We are seeing the same behavior from MSVC and GCC compilers. I can try master with GCC here too but sounds like that fix is unrelated? I'll try to glean more useful data from logs I have here. We distribute encrypted assets to lots of machines (all running Windows) but I have to dig around some. On Friday, September 17, 2021 at 12:23:55 AM UTC-7 Jeffrey Walton wrote: > On Thu, Sep 16, 2021 at 8:42 PM austin clifton <austin....@otoy.com> > wrote: > > > > I have an issue which I believe may be a bug. I followed the > instructions from the "Bug Report" page on the cryptopp wiki and all tests > in cryptest.exe are passing, so figured I should post here first and make > sure it isn't a build related issue. > > > > I built cryptopp 8.5.0 as a static library, x64 multi-threaded debug > (\MTd) using Visual Studio 2019 v16.10.0, on Windows 10 Pro v10.0.19043, > using the .sln file provided with the cryptopp source code. > > > > I used two different machines for this test. One is the machine I built > the cryptopp library with. Both are running the same version of Windows 10. > One machine has a Ryzen 3700X, the other has an i7-990X. The Ryzen supports > AVX, the i7 does not. > > > > I am VERY rarely finding that files encrypted with the chacha cipher by > these two machines have differing sha256 hashes. If I do a hex diff against > the files, there is a single flipped bit at 0x1EBB4 (0xD8 vs 0xD9). > > > > I am able to reproduce this consistently with a specific key, nonce, and > input file, after test encrypting ~50GB of 1MB garbage files on each > machine. > > > > If I disable AVX when building cryptlib by defining CRYPTOPP_DISABLE_AVX > and CRYPTOPP_DISABLE_AVX2, the machine with the Ryzen will encrypt the file > the same as the i7. > > > > Source code for a minimal reproducible example is here: > > > https://github.com/austin-clifton/cryptopp-chacha-asm-test/blob/main/src/main.cpp#L208 > > > > That repository includes a ready-to-build test case with Visual Studio, > minus a built cryptlib.lib which should be added to libs/debug/ before > building. > > Austin, > > I fetched main.cpp and run_459_file_76.bin from your GitHub. I > compiled the library with: > > CXXFLAGS="-DNDEBUG -g2 -O3 -std=c++17" make > > I compiled/linked main.cpp with: > > g++ -DNDEBUG -g2 -O3 -fPIC -pthread -std=c++17 -I. main.cxx > ./libcryptopp.a -o main.exe > > Running the program on a AMD Ryzen 3 3200U and AMD A6-9220e, this is the > result. > > $ ./main.exe > sha256: 0FC0FADCDF82770086C9DA8513A16FC785620D7B1C187CDD828E433EB0979847 > encsha: 6FBEE484EE64A2AB02235DDF29CA0B61EE3B811D227C2729836D3BD6161C9B18 > > Is this correct? > > I have one Windows machine for testing. It is a Core i5. Sorry I don't > have a good test environment. > > Jeff > -- You received this message because you are subscribed to the Google Groups "Crypto++ Users" group. To unsubscribe from this group and stop receiving emails from it, send an email to cryptopp-users+unsubscr...@googlegroups.com. To view this discussion on the web visit https://groups.google.com/d/msgid/cryptopp-users/50ee9fd1-c7be-414d-a8b4-84b8fa7bac2an%40googlegroups.com.
