Substitution Cipher Puzzle

The solved phrase, "So we beat on, boats against the current," is a poignant and iconic line from a cornerstone of American literature. It powerfully encapsulates the human struggle against the inevitable flow of time, the pull of the past, and the persistent, often futile, pursuit of dreams. The quote speaks to our enduring hope and resilience, even when faced with insurmountable odds or a predetermined fate.

This memorable closing comes from F. Scott Fitzgerald's masterpiece, "The Great (Review) Gatsby." Fitzgerald, a prominent figure of the Jazz Age, was known for his vivid portrayals of the Roaring Twenties, exploring themes of wealth, class, idealism, and the elusive American Dream. His own life, marked by both dazzling success and personal turmoil, often mirrored the grand aspirations and tragic disillusionment found in his fiction, giving his work a deeply personal and resonant quality.

The puzzle you've just unraveled employs a substitution cipher, a fundamental method in the history of secret communication. In this type of cipher, each letter of the plaintext is consistently replaced by another letter or symbol. Substitution ciphers have been used for millennia, with early examples like the Caesar cipher dating back to ancient Rome, demonstrating humanity's long-standing fascination with securing messages and the intellectual challenge of breaking codes.