Git repositories of interest to tilde users.
An interactive explorer of the disassemblies of the BASIC ROMs and kernels for the various versions of the Commodore 64. Each ROM is disassembled and lined up side by side so you can see what's different between versions and hardware releases.
A utility which can be used to recover the passphrase for a PGP or GnuPG key.
An impressive collection of research papers, exploits, and utilities.
A framework used by penetration testers for building custom exploits for infiltrating systems. Written in Ruby. Comes with a large library of payloads and other nifty and fascinating tools. It's worth learning to use if you're serious about penetration testing or exploit development. Also, the cutting edge of attack technologies winds up coming out of the Metasploit project.
A free, online book on the C programming language. There is also a downloadable .pdf file of the contents of the e-book so you don't have to try to archive the whole website.
An open source set of libraries and tools written in Python for interacting with RFID and NFC chips.
Someone fed ROM dumps from a couple of Atari games into distellamap and generated maps of function calls, with sprite dumps. Amazing, how simple games were back then...
An open source decompilation application that helps the user reverse engineering applications. Retargetable to different CPUs, so you can (say) reverse a SPARC binary on a PowerPC machine. Modular.
An open source utility that will crack the password used to encrypt .rar, .zip, and .7z archives. Runs multi-threaded to speed things up because it uses a brute-force attack.
Give the web application on this site a URL, some text, a phone number, or an SMS code and it'll generated a 2d barcode called a QRcode, which you can save as a .png file to use as you like. Good for stickers, business cards, and other ways of making some data machine readable and scannable.
A disassembler for Windows. One of the best in the field, and v2.0 just went beta. It's shareware, though it doesn't appear to lack any functionality if you haven't purchased it yet.
Paste two blocks of text into the forms on this website and it'll show you the differences between them.
An excellent blog post on how Wordpress backdoors work, how they're hidden, and how they're used.
Just like in the movies, type random keys into this web app and it'll print nifty-keen-like-wow source code onto the screen.
A Subversion tutorial written for software developers and not sysadmins or repository maintainers. Teaches you what you need to know in order to get work done.
code development software subversion revisioncontrol svn tutorial