Top all-time · #697
corte.si
Personal blog · corte.si · on HN as cortesiprogrammingsecuritydata
corte.si is a personal blog at corte.si about programming, security and data. Since 2009, 89 different Hacker News readers have linked it 142 times, most often “Visualizing binaries with space-filling curves”. It is still writing: the last post was on 2026-01-28, and you can follow it by feed.
Sometimes recommended · 9 of 31 sampled comments recommend it?
Why HN links it
HN readers link Aldo Cortesi's posts on visualizing sorting and binary files, which commenters call useful, and his host-proof encryption writing.
- Recommended for · 9 comments
- Called useful, "spot-on" and interesting; visualizations preferred to animations; host-proof posts recommended.
Summarised by Claude from a sample of 31 HN comments that link here. Each comment is marked recommending, critical or neutral (citing without judging); how this works.
Most-linked posts?
- Visualizing binaries with space-filling curves5 people · 6 mentions · first linked 2011-12-23
- Visualising Sorting Algorithms (2007)5 people · 5 mentions · first linked 2010-12-12
- Visualizing sorting algorithms with Hilbert curve5 people · 5 mentions · first linked 2010-01-26
- A survey of how Apple UDIDs are used by apps4 people · 5 mentions · first linked 2011-05-19
- Host-proof applications: doing it wrong4 people · 5 mentions · first linked 2010-02-26
- Why the Apple UDID had to die4 people · 5 mentions · first linked 2011-09-19
- The impact of language choice on github projects4 people · 4 mentions · first linked 2009-12-14
- Cryp.sr - a minimal host-proof cryptographic textpad4 people · 4 mentions · first linked 2010-03-29
- Visualizing entropy in binary files4 people · 4 mentions · first linked 2012-01-05
- Reading Code: In praise of superficial beauty4 people · 4 mentions · first linked 2009-12-14
What Hacker News says?
This is huge. I've been fearing this kind of leak for a long time. If you're unsure why this is huge, here are some posts of mine on this issue showing de-anonymization, complete takeover of social media accounts, and more: De-anonymizing UDIDs with OpenFeint: http://corte.si/posts/security/openfeint-udid-deanonymizatio... A survey of how UDIDs are used: http://corte.si/posts/security/apple-udid-survey/index.html Wh…
Comment linking /posts/security/udid-must-die/index.html
on “AntiSec leaks 1,000,001 Apple UDIDs, Device Names/Types”Submitted Show HN: Mitmproxy 1.0 released, now with a web interface as a story · 248 points
HN discussionHmmm, it seems that despite removal of the personal info, there may be ways to link it back to partial profiles via OpenFeint... http://corte.si/posts/security/openfeint-udid-deanonymizatio... also: http://corte.si/posts/security/udid-must-die/index.html
Comment linking /posts/security/udid-must-die/index.html
on “AntiSec leaks 1,000,001 Apple UDIDs, Device Names/Types”Submitted Devd: a small, self-contained web daemon for developers as a story · 229 points
HN discussionI can't speak for himself, but BSDs, especially NetBSD and OpenBSD are known for their code quality. Quoting from "What is NetBSD?"[1]: "The basic features of NetBSD are: Code quality and correctness ...". [1] http://www.netbsd.org/docs/guide/en/chap-intro.html [2] http://corte.si/posts/code/reading-code.html
Comment linking /posts/code/reading-code.html
on “Linus Torvalds won't do github pull requests”Submitted Visualizing binaries with space-filling curves as a story · 160 points
HN discussionI'm getting a 508 error... But somewhat related, and I think was on HN at some point: http://corte.si/%2Fposts/code/hilbert/portrait/index.html
Comment linking /%2Fposts/code/hilbert/portrait/index.html
on “All RGB colors in one image”Submitted Introducing choir.io as a story · 154 points
HN discussionReminds me of the (sadly) now defunct choir.io. Intro post > https://corte.si/posts/choir/intro/choir.html They had a demo of Github realtime activity and I hooked it into a bunch of different events around the org - Salesforce/Yammer/Github/JIRA - was neat to have a "pulse" of daily activity in the background.
Comment linking /posts/choir/intro/choir.html
on “GitHub Audio”Submitted Go: a nice language with an annoying personality as a story · 151 points
HN discussionI published a tiny script that makes mass grabbing of files from Github easy ( https://github.com/cortesi/ghrabber ), and wrote about some of the interesting things one could find with it. For example, there are hundreds of complete browser profiles on Github, including cookies, browsing history, etc: http://corte.si/posts/hacks/github-browserstate I've also written about some less security critical things, like she…
Comment linking /posts/hacks/github-pipechains
on “Survey of popular Node.js packages reveals credential leaks”Submitted How mitmproxy works as a story · 120 points
HN discussionI'm somewhat late to the party, but I spent some time playing with procedural colour picking using space-filling curves (the Hilbert curve in particular). I describe the basic technique here: http://corte.si/posts/code/hilbert/portrait/index.html And you can see what this looks like when used to visualize sorting algorithms at large scale here: http://corte.si/posts/code/sortvis-fruitsalad/index.html And here: http:…
Comment linking /posts/code/sortvis-fruitsalad/index.html
on “How to Choose Colours Procedurally”Submitted The UDID leak is a privacy catastrophe as a story · 119 points
HN discussionNice, though I think static visualizations illustrate the examples more quickly and are easier to compare: http://corte.si/posts/code/visualisingsorting/index.html I also love Robert Sedgewick's technique of using angle to encode array value. Animated and static examples here: http://bl.ocks.org/1243323 http://mbostock.github.com/protovis/ex/sort.html
Comment linking /posts/code/visualisingsorting/index.html
on “Show HN: Write a sort, watch it go”Submitted Visualizing binaries with space-filling curves (2011) as a story · 110 points
HN discussionYou might find this useful: http://corte.si/posts/visualisation/binvis/index.html and related: http://corte.si/posts/visualisation/entropy/index.html (visualizing entropy in binary files) I used his software on an unknown format from the 1988 game Circuit's Edge to find out if/where the file was encrypted or compressed. It works well and was able to give me a (very) general idea of where in the file I needed to look…
Comment linking /posts/visualisation/entropy/index.html
on “Static analysis of an unknown compression format”Submitted De-anonymizing Apple UDIDs with OpenFeint as a story · 100 points
HN discussionIt's not really true that (due to the data being encrypted client side) your data is safe even if someone were to gain control of the server. It's something often claimed by these "Host Proof" style services. As long as you are downloading the client side code from the server, someone just needs to make a small change to the javascript and they get access to your data. Only if you can trust the code, and then make c…
Comment linking /posts/security/crypsr.html
on “ZeroBin, opensource Pastebin where the server has zero knowledge of pasted data”Submitted The impact of language choice on github projects as a story · 99 points
HN discussionAgreed re: the quality of Frank McSherry's posts - they're all great fun and push the technical envelope! I'm glad you brought up Hilbert ordering. It's fascinating but I rarely see it. I usually see Z-order curves in their place - simpler and more intuitive but also less effective. Does anyone know of large scale databases with Hilbert ordering out of the box? For anyone who hasn't seen them before, or why they hel…
Comment linking /%2Fposts/code/hilbert/portrait/index.html
on “One trillion edges: graph processing at Facebook scale [pdf]”Submitted How to stop a story from appearing on Reddit as a story · 94 points
HN discussionAnother example of Hilbert curves used for trawling the RGB cube: http://corte.si/posts/code/sortvis-fruitsalad/index.html (And, of course, IP addresses: http://xkcd.com/195/ )
Comment linking /posts/code/sortvis-fruitsalad/index.html
on “A practical use for space-filling curves”Submitted Reading Code: In praise of superficial beauty as a story · 91 points
HN discussionThe first demo of bubble sort made me think the bottom row was being sorted and then the rows above were just the previously sorted row. I like Aldo's visualizations a bit better: http://corte.si/%2Fposts/code/sortvis-fruitsalad/index.html
Comment linking /%2Fposts/code/sortvis-fruitsalad/index.html
on “Rainbow Sort Visualisations”Submitted Visualizing binaries with space-filling curves (2011) as a story · 80 points
HN discussionHumans are awesome at recognizing visual patterns. It's difficult to get a sense of what a file contains from a hex editor, but if you apply the right transformations on the data, distinct features stand out in the visualization. This allows people to recognize similarities between different files as the resulting patterns are revealed. Take this previous blog post by the same author: http://corte.si/posts/code/sort…
Comment linking /posts/code/sortvis-fruitsalad/index.html
on “Visualizing binaries with space-filling curves”Submitted Things I found on GitHub: shell history as a story · 80 points
HN discussionWhy, hello there Hacker News. Just a note that I've written two follow-on blog posts after this one, developing the idea a bit further. First, using a color function that encodes local entropy to show how crypto keys and other high-entropy data can be picked straight out of a visualization: http://corte.si/posts/visualisation/entropy/index.html And next, using this in bulk on samples from a malware database, with wh…
Comment linking /posts/visualisation/malware/index.html
on “Visualizing binaries with space-filling curves”Submitted The impact of language choice on github projects as a story · 72 points
HN discussion
