Comment by strenholme
3 hours ago
“Rolling your own crypto libraries is always a bad idea”
Absolutes like this aren’t absolutely true.
It’s interesting because in a related comment, someone claimed that I was “rolling my own crypto” >>>a few odd coding decisions, such as rolling your own crypto (RNG)<<< Let me give some context here. MaraDNS is a DNS server that’s been around for a very long time, since 2001. There has never been, in those 25 years, any security holes found having to do with the RNG code used by MaraDNS. MaraDNS originally used an AES variant for the RNG; when DJB found cache timing attacks a little over two decades ago, I revised the AES-based RNG code to minimize the impact of such impacts, making the code slower and more complicated. So, about two decades ago, I implemented a new RNG based on RadioGatún, an algorithm which isn’t vulnerable to cache timing attacks and, indeed, has no known attacks which break its cryptographic claims, even though those claims were made over two decades ago. My code has been extensively audited by multiple AI-based security researchers, and while they found two minor issues with the DNS-over-TCP code in the recursive resolver, and a minor issue with the RFC8482 reply in the recursive resolver, no issues have ever been found with the RNG code in MaraDNS (except the issue with possible cache timing attacks I fixed myself after learning about them). [1] In the same time period, OpenSSL has had a large number of security issues, security advisories, and so on. OpenSSL has had countless security holes and patches in the last two decades (Heartbleed, etc.); MaraDNS has had precisely 0 known issues with its RNG code in the same time period. If I had relied on OpenSSL to keep MaraDNS’s cryptography secure, it would had been exposed to many more attacks than it has, since the code I rolled myself ended up being far more secure than using the code in a third party library. Point being, it is possible for someone to roll their own secure RNG. I wouldn’t do so in a corporate context, for the simple reason management often times puts unreasonable time constraints on developers, but for an open source project developed on my own timeline, it can be, in fact it has been very secure. Also: I was never exposed to the Lastpass breach because, instead of using Lastpass, I rolled my own secure website password generator. [2]
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