Substitution Cipher Puzzle

This iconic line, a poignant farewell from a beloved cinematic classic, perfectly encapsulates the bittersweet romance and noble sacrifice at the heart of the story. "Here's looking at you, kid" is uttered by Humphrey Bogart's character, Rick Blaine, to Ingrid Bergman's Ilsa Lund in the 1942 American romantic drama film *Casablanca*. It's a moment steeped in enduring affection and a reluctant acceptance of fate, conveying a deep, sentimental connection despite their impending separation for a greater cause. The phrase, while popularized by the film, was used as a toast before *Casablanca*'s release.

The movie itself, a timeless masterpiece, won multiple Academy Awards, including Best Picture, solidifying its place in film history. Interestingly, Bogart reportedly improvised this particular line, first using it casually off-camera before incorporating it into the script, making its legendary status even more remarkable. The puzzle you solved utilizes a substitution cipher, a fundamental cryptographic technique where each letter in the original message is consistently replaced by another. This method, a cornerstone of early message security, has roots stretching back to ancient times, with variations like the Caesar cipher being early examples used by civilizations to protect communications long before the digital age.