HOW I REVERSED AMAZON'S KINDLE WEB OBFUSCATION BECAUSE THEIR APP SUCKED

Summary from the TLDR InfoSec newsletter

Frustrated by Amazon's Kindle app instability and restrictive DRM, this author set out to reverse-engineer Amazon's web obfuscation system. Instead of granting simple access to purchased ebooks, Amazon uses a system where the actual text is encoded as glyph IDs rather than characters, with the mapping randomized for every batch of pages. Overcoming these sophisticated protections required pixel-level glyph matching and leveraging font metrics to reconstruct the book, eventually allowing the owner to access their purchase in a way they controlled.