Replacing libDwmAuth due to Crypto++ problems

This has been a while in the making, but…

I am in the process of replacing libDwmAuth with a new library I’m calling libDwmCredence. Why?

Mainly due to poor maintenance of Crypto++, which I used in libDwmAuth. Quite some time ago I tried to explain two problems with Crypto++ to the maintainers that led to memory leaks and corruption on some platforms. I gave up due to the current maintainers not resolving the problem, and growing tired of maintaining my own fork in a private repository. The root of the issue was an incorrect optimization and attempt at forced alignment. In essence, an attempt at optimization that critically destroyed the integrity of the library on some platforms (notably an important IoT platform I use, Raspbian). The last place you want code to stomp on the stack or heap is in your crypto library!

Way back when, I used Crypto++ because it was FIPS validated. That hasn’t been true for a while, and it doesn’t appear that it will be true in the future. Then when elliptic curve solutions came along, Crypto++ was very slow to adopt due to design contraints. This was troublesome for me since some IoT platforms don’t have hardware acceleration for AES, and hence I wanted to be able to use XChaCha20poly1305 and the like to improve performance, as well as Ed25519 and X25519 keys. There was a period where I couldn’t do this at all with Crypto++.

Finally, for my own work, I don’t really need much of what Crypto++ provides. And parts of the interface use C++ in atypical ways, making code hard to read.

So, I’ve switched to libsodium and wrapped it with C++. While there are many things I don’t like about libsodium, it provides what I need and I am able to make it safer by wrapping it. Furthermore, I am using boost::asio and a semi-elegant wrapper that allows me to send and receive just about anything on the wire easily. It does what I need it to do, and no more. Of course the boost::asio interfaces are considerably different than socket()/bind()/select()/accept()/connect()/etc. but I mostly only have to think about that on the server side.

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