SHA-1 collider: Make your own colliding PDFs

Re:SHA-1 collider: Make your own colliding PDFs by lucb1e on Friday February 24, 2017 @04:26PM (#13728058)

(not OP) I understand why the requirements are strict so I can see why s/he was being downvoted, but I do agree that samples would be nice. Like, do I have to go search for some images with these requirements just to see if it really works (since it was supposed to take $100k)? By now someone mentioned it works in the comments though, so I guess I'll trust them.

[ Parent | on HN ]

Re:SHA-1 collider: Make your own colliding PDFs by shaymcrasherson on Friday February 24, 2017 @04:53PM (#13728272)

Is it really that hard to take a screenshot of a couple windows on your desktop and run:

$ convert screenshot.png -resize '500x500!' bar.jpg

$ sips -s format jpeg -Z 500x500 screenshot.png --out bar.jpg

Generating some workable source images is trivial. You're not interested in making a 'perfect hack pdf' for some nefarious purpose, just seeing if the service does what it says it does.

[ Parent | on HN ]

Re:SHA-1 collider: Make your own colliding PDFs by ythn on Friday February 24, 2017 @05:53PM (#13728695)

> Generating some workable source images is trivial

Everything is trivial if you know how to do it off the top of your head. Generating white noise samples is trivial. UV-mapping a texture to a mesh is trivial. Soldering resisters to a PCB is trivial. Generating an ARM toolchain with Yocto Project is trivial.

Is it a crime that I didn't feel like researching a bunch of CLI tools I've never heard of to try to use an app I was only mildly curious about?

[ Parent | on HN ]

Re:SHA-1 collider: Make your own colliding PDFs by TazeTSchnitzel on Friday February 24, 2017 @09:08PM (#13729561)

This overstates the difficulty of creating a JPEG. If you have an image editor on hand that isn't MS Paint (or you're using macOS, which has Preview), you merely need to export a JPEG and choose a low quality setting.

For a Windows user with no decent image editor or viewer installed, though, it could certainly be a hassle.

[ Parent | on HN ]

Re:SHA-1 collider: Make your own colliding PDFs by ythn on Saturday February 25, 2017 @12:11PM (#13732490)

None of the things I listed are difficult. They just require the right tool and know how. For someone like me with Xubuntu, I had neither the tools nor know how for creating small jpegs. I didn't fell like wasting 30 minutes researching and I didn't feel like walking over to a different computer that has MSPaint.

[ Parent | on HN ]