j2winSoftware engineer & security enthusiast. Writeups, CTFs, tooling, and hands-on labs you can follow along with.https://j2win.me/CyLab Security Academy - RSA write-upshttps://j2win.me/blog/cylab-rsa-writeup/https://j2win.me/blog/cylab-rsa-writeup/Thinking through a little nibble of RSA.Sun, 04 Oct 2026 00:00:00 GMTpythoncryptowrite-upctfCyLab Security Academy - "New Caesar" writeuphttps://j2win.me/blog/new-caesar-cylab-writeup/https://j2win.me/blog/new-caesar-cylab-writeup/My thought process for solving this crypto challenge.Thu, 01 Oct 2026 00:00:00 GMTpythoncryptowrite-upctfBuilding jwt-autopsy and portscouthttps://j2win.me/blog/jwt-autopsy-and-portscout/https://j2win.me/blog/jwt-autopsy-and-portscout/Two small security tools I wrote to learn how the real ones work: an async TCP port scanner in Python and a JWT inspector in Go.Fri, 25 Sep 2026 00:00:00 GMTtoolingpythongonetworkingweb securityHow to follow along with this bloghttps://j2win.me/blog/how-to-follow-along/https://j2win.me/blog/how-to-follow-along/A quick tour of the interactive terminals, runnable code cells, and hints you will find in every post.Tue, 01 Sep 2026 00:00:00 GMTmeta