"The Gold-Bug" includes a cipher that uses polyphonic substitution. Though he did not invent "secret writing" or cryptography, Poe certainly popularized it during his time. To most people in the 19th century, cryptography was mysterious and those able to break the codes were considered gifted with nearly supernatural ability. Poe had drawn attention to it as a novelty over four months in the Philadelphia publication Alexander's Weekly Messenger in 1840. He had asked readers to submit their own substitution ciphers, boasting he could solve all of them with little effort.
Poe wrote "The Gold-Bug" as one of the few pieces of literature to incorporate ciphers as part of the story. Poe's character Legrand's explanation of his ability to solve the cipher is very like Poe's explanation in "A Few Words on Secret Writing.
Poe's depiction of the African servant Jupiter is often considered stereotypical and racist from a modern perspective. Jupiter is depicted as superstitious and so lacking in intelligence that he cannot tell his left from his right. Black characters in fiction during this time period were not unusual, but Poe's choice to give him a speaking role was. Critics and scholars, however, question if Jupiter's accent was authentic or merely comic relief, suggesting it was not similar to accents used by blacks in Charleston but possibly inspired by Gullah.
Though the story is often included amongst the short list of detective stories by Poe, "The Gold-Bug" is not technically detective fiction because Legrand withholds the evidence until after the solution is given. Nevertheless, the Legrand character is often compared to Poe's fictional detective C. Auguste Dupin due to his use of "ratiocination.
"The Gold-Bug" inspired Robert Louis Stevenson in his novel about treasure-hunting, Treasure Island (1883). Stevenson acknowledged this influence: "I broke into the gallery of Mr. Poe... No doubt the skeleton [in my novel] is conveyed from Poe....