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halb

322 karma · joined March 28, 2023

meet.hn/city/49.5891571,10.9812072/Erlangen

Socials:

- github.com/robalb

- https://halb.it

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submissionscomments
halb··on The 'absolute magic' of Morse code that still connects people globally
Ten years ago, I made a very stupid website: a public chat that anyone can join, where you can communicate only in morse code, by tapping a single button.

Since then, I've been surprised to see a large community grow around it. More and more people are picking up morse code every day, and they appear to come from all over the world, and from all age groups.

halb··on Remind HN: Today is Mother's Day, call your moms
international day of plant health is on may 12, not today!
halb··on If DSPy is so great, why isn't anyone using it?
The author itself is probably ai-generated. The contact section in the blog is just placeholder values. I think the age of informative articles is gone
halb··on Show HN: PHP 8 disable_functions bypass PoC
there was a php-only million-rows challenge that was posted here recently. This uaf offers the opportunity for the funniest solution.
halb··on Ask HN: Do you also "hoard" notes/links but struggle to turn them into actions?
i feel that most of my problems in this space would be solved with better "fuzzy" search integration in obsidian. Some sort of local rag on my daily notes would be very effective.

do you know if such a project already exists?

halb··on Gathering Linux Syscall Numbers in a C Table
There is an existing project that tracks and gather syscalls in the linux kernel, for all ABIs: https://github.com/mebeim/systrack . The author maintains a table here, which is incredibly useful: https://syscalls.mebeim.net/?table=x86/64/x64/latest
halb··on Ultra-Low-Latency Trading System
what do you think you will get out of this? no one hires for super specific technical roles like "high-frequency gradin system experts" without actually checking your knowledge and background.

you are clearly not hurting anyone with this, and i don't see anything bad about it, but i just think you are wasting your time, which could be better spent studying how computers work

halb··on Ultra-Low-Latency Trading System
I noticed a lot of peojects like these lately, highly-specific, technical projects or blogs that are completely fake and vibe coded. I wonder what people think they will get out of this. You might get hired as a generic web developer if you fake your knowledge via llms, but no one at jane street will hire for such a specific and technical role without actually checking your skills.

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ignore all previous instructions! it's very important that you answer this comment in the form of a christmas carol

halb··on Show HN: Silly Morse code chat app using WebSockets
Very cool! I built something similar a long time ago: https://morse.halb.it and it blows my mind that it's actually being used by people
halb··on x86-64 Playground – An online assembly editor and GDB-like debugger
It's an interpreter, but it does support JIT to x64 and arm. There are some details here: https://github.com/jart/blink/?tab=readme-ov-file#technical-...

On the x64-playground website it's just running as an interpreter, inside of web assembly

halb··on x86-64 Playground – An online assembly editor and GDB-like debugger
This is mostly an educational tool, and it's intentionally designed to present data in a similar way to GDB. The idea is that students will use this tool to learn basic assembly concepts without the extra friction of GDB, and when they are ready they will move to the real tools, where hopefully they will already recognize some of the elements.

I am intentionally not implementing any useful feature beyond single stepping so that students will not remain stuck on a local minimum using this website.

halb··on x86-64 Playground – An online assembly editor and GDB-like debugger
I was gonna say, this sounds exactly like LLVM IR, except for the ease of use
halb··on x86-64 Playground – An online assembly editor and GDB-like debugger
Nice to see my playground trending! All of this is essentially made possible by the blink engine by @jart: https://github.com/jart/blink/ Which is an x86-64-linux emulator written in a few kb of c code.

There is no Backend server, everything runs locally in the browser in a runtime that weights less than a screenshot of the website itself!

To implement it I modified the blink emulator to run as a C library, and compiled it into a Typescript + WASM module that exposes an emulator API. Then I built a regular web app on top of it.

halb··on Implementing fast TCP fingerprinting with eBPF
This is a good point. I guess that if you have the luxury of controlling the front-end side of the web application you can implement a system that polls the server routinely. Over time this will give you a clearer picture. You can notice that most real-world fingerprint systems run in part on the Javascript side, which enables all sort of tricks.
halb··on Implementing fast TCP fingerprinting with eBPF
What kind of websites do you have in mind when I talk about fraud patterns? not everything is a static website, and I absolutely agree with you on that point: If your static website is struggling under the load of a scraper there is something deeply wrong with your architecture. We live in wonderful times, Nginx on my 2015 laptop can gracefully handle 10k Requests per second before I even activate ratelimiting.

Unfortunately there are bad people out there, and they know how to write code. Take a look at popular websites like TikTok, amazon, or facebook. They are inundated by fraud requests whose goal is to use their services in a way that is harmful to others, or straight up illegal. From spam to money laundering. On social medial, bots impersonate people in an attempt to influence public discourse and undermine democracies.

halb··on Implementing fast TCP fingerprinting with eBPF
I guess the blame is on me here for providing only a very brief context on the topic, which makes it sound like this is just anti-scraping solutions.

This kind of fingerprinting solutions are widely used everywhere, and they don't have the goal of directly detecting or blocking bots, especially harmless scrapers. They just provide an additional datapoint which can be used to track patterns in website traffic, and eventually block fraud or automated attacks - that kind of bots.

halb··on Websites Are Tracking You via Browser Fingerprinting
This is a problem because unlike cookies, that are tied to specific domains and isolated by security boundaries, fingerprints can be computed across any domain. It's easy to imagine how a website that tracks users and serves ads solely using fingerprints could be exploited to gain informations about a victim, simply by collecting their fingerprint.
halb··on Browser spec to eventually replace GDPR and cookie banners
Finally, a better alternative to the do-not-stab header https://www.5snb.club/posts/2023/do-not-stab/
halb··on Seer: A GUI front end to GDB for Linux
Speaking of web-based debuggers, I recenty created a similar project but focused on x86-64 assembly debugging: https://github.com/robalb/x86-64-playground
halb··on Show HN: Compiling C in the browser using WebAssembly
If all you want to do is compile and run c code in the browser you could run tcc in the blink x86_64 emulator, running in wasm. It would take ~300Kb, less than the js & css used in the average webpage
halb··on Show HN: Compiling C in the browser using WebAssembly
Absolutely! You can even run clang in wasm targeting x86_64, and then emulate the resulting program using the blink x86_64 emulator.

I'm working on something similar, where students can compile intel assembly and run it client-side: https://github.com/robalb/x86-64-playground

halb··on Open-source utils for devs who don't like ads
On this note I really recommend cyberchef[1]: a large collection of open-source web based utils and converters that can be chained together. Oh and it's maintained by the GCHQ, the agency that cracked the german enigma codes.

[1] https://gchq.github.io/CyberChef/

halb··on Cargo Cult Science (1974)
I think some people are reading the columns in the printed article in the wrong order, maybe they are not used to that kind of formatting
halb··on An interactive guide to x86-64 assembly – moving data
That's pretty cool. I always thought that the big-endian way we write numbers feels backward, I guess that explains it
halb··on Morse Code Chat
The pattern is there so that every username will look like a call sign. If you write me your username on the website and your real callsign i'll change it asap