Decoding the 90s: Cryptography in Early Software Development (2023)

Intro In August 2020, we were commissioned by a client with a cache of locked QText documents from the mid 90s - to which he has lost the passcode. QText was a DOS era Hebrew-English word processor written in Turbo Pascal, released 15 or so odd years before neither I nor @Elisha had laid hands on a reverse engineering tool. In this blog post, we’ll describe the process of analyzing the encrypted documents and reverse engineering a DOS program. Hopefully we’ll be able to provide some insight into the early days of software development in Israel, and more generally into how cryptography was viewed and implemented in the early days of consumer software development. We also hope to help preserve the knowledge and tools utilized here - a lot of which have scarcely survived to this day. Getting started - QText Luckily, we had access to working QText binaries, supplied by our client. We loaded up an instance of the DOSBOX emulator and proceeded to pla ... Read full article.