Comment by 63
11 hours ago
A bit unfortunate that so many of the interesting bits were left to ai. I would've enjoyed some commentary on why the custom TLS implementation was necessary. Oh well.
Update: found this explanation in a comment at the top of the (surprisingly short) Go file in the linked repo:
The target client is Netscape Communicator 4.51 (both the 40-bit export build and the 128-bit US build) with its clock set to the year 2000.
Go's crypto/tls cannot help: it dropped SSLv3 in Go 1.14, never accepted the SSLv2-compatible ClientHello that Netscape 4 sends, and never had RC4-MD5 or the 40-bit export suites. So this file carries its own tiny SSLv3 server-side implementation on top of stdlib primitives (RSA PKCS#1 v1.5, RC4, DES, 3DES, MD5, SHA-1). The server key is 512-bit RSA so that export clients can encrypt the premaster secret to it directly, without a ServerKeyExchange.
(As the author of the post)
I've written and worked on a few TLS implementations, so it wasn't terribly interesting to me. And I have to go to work tomorrow and solve real, modern CA problems :)
But in short, I wanted to use Go, and it doesn't support SSLv3, the SSLv2 Client Hello, or the 40-bit RC4-MD5 export-grade cipher suites which I wanted to support too.
I was more shocked that I managed to get stock OpenSSL to issue a certificate that worked. There's a number of things that didn't work there, too. You can find my scars in mkcert.sh in the repo. Perhaps all of this is worthy of a follow-up post.
I could have tried to get some old server running instead, but I wouldn't have wanted to deploy that on the internet, even on an isolated Fly VM.
Strange seeing how people have such a hard time seeing others using AI and seem to want to complain about it instead of just, well, asking AI why something was likely done a way. It works both ways my dudes, experts don’t need to explain every last detail, prompt a bot with the context until you understand.
From my prospective, the outputs of a bot aren’t the interesting bits, it’s the input prompt that should warrant more attention.
I bet all the certificate metadata shown in the „View a certificate“ popup window is vulnerable to cross-site scripting. Back then you probably wouldn’t get a <script> tag through a CA's review process and I found such a problem in Netscape's image „About page“ popup.
If it were vulnerable to XSS, why would you even want it properly signed by a CA? People almost never inspect the certificates of working websites, the only time they might look at it is when it fails validation.
Probably because modern libraries dropped support for ancient insecure SSL. Backwards compatibility is really not a valued thing for that area.
A while back I helped a friend (read: dumped a bunch of compute power into it) brute force the SSL keys for Sega's "Phantasy Star Online" Dreamcast game.
They used a similar kind of custom (and flawed) TLS implementation in their game(s) which allowed signing new certificates after brute forcing.
The benefit to this is that users can now play these games without needing to burn a new CD with either the SSL certs swapped, or the code patched to dummy out the checks. A "retail CD" will simply work with private servers now.
I've also been on the other side of the fence, building a "retro internet" service [1] has meant trying to implement ancient SSL/TLS services for things and people that want to use them on the network.
Getting modern OpenSSL (aka what ships in Debian) to even accept these ciphers, let alone keys that short is an uphill battle. Understandably, they're disabled by default and (in Debian at least) the cipher support isn't even compiled into the binary! This requires building a custom OpenSSL to build Nginx against to serve ancient SSL.
Presumably for the OP this kind of work was either outside of their realm of knowledge, or simply "easier" to outsource to the slop machine. Though I hope the machine they're running their demo TLS implementation on is separated completely from their own network. Rolling your own crypto libraries is always a bad idea [2] and I doubt LLM's have "improved" that
[1] https://www.youtube.com/watch?v=cSJsGNIDjtc
[2] https://soatok.blog/2025/01/31/hell-is-overconfident-develop...
“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.
[1]ricksunny
8 hours ago
smaudet
11 hours ago
CursedSilicon
11 hours ago
throw1234567891
5 hours ago
(I have next to zero knowledge of matters crypto)
“Presumably for the OP this kind of work was either outside of their realm of knowledge,”
Unnecessary? I don’t even follow the statement’s framing even if I validated the apparent nerdswipe tendency.
For what it's worth, this comment was better than the article...
When you outsource to the slop machine, you don't have anything interesting to say (usually).
Oh, I have *strong* opinions about the slop machine. But I try to temper them so I don't get buried by the usual "pro AI" mob
I will say that my projects have a "leading the pack" anti-AI policy [1]
[1] https://wiki.cursedsilicon.net/wiki/AI_Policy
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The slop machine gives answers to your questions. It hallucinates so it's recommended to verify what it says. Shit in, shit out. If you have no idea whatsoever and can't use other sources to verify claims, well, get a different job I guess.
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