From Spartan batons to FBI stings, the secret history of hidden writing is ancient.

History · Published 3 October 2026 Swipe more like this →

In short: Cryptography is not just a digital phenomenon; it is an ancient art of concealment. From the Spartan scytale to the FBI's deceptive ANOM messaging app, the struggle between those who hide information and those who break codes has defined human communication for thousands of years, evolving from simple batons to supercomputers.

The history of cryptology is traditionally divided into three distinct phases. The first, manual cryptography, spanned from antiquity through World War I. During this era, security was constrained by the speed and complexity of what a human clerk could achieve using simple mnemonic devices. Early methods included the Spartan scytale, a tapered baton used around 400 BCE, and the Caesar cipher, which shifted alphabet positions. By the 9th century, the Arab scholar al-Kindi revolutionized the field by documenting frequency analysis, a technique that exploited language patterns to break monoalphabetic substitution ciphers, rendering many previously secure codes vulnerable.

The second phase, the mechanization of cryptography, emerged after World War I. This period introduced electromechanical devices like rotor machines, which utilized gears, ratchets, and cams to perform complex operations far beyond human manual capacity. These machines allowed for the encryption of significantly larger volumes of data with fewer errors. By the end of the 20th century, the shift toward electronic and silicon-based systems accelerated this trend, enabling the processing of trillions of bits of ciphertext per second. This evolution turned the cat-and-mouse game of code-breaking into a high-speed technological arms race.

The third phase, beginning in the late 20th century, extended cryptology into the digital information age. This era introduced digital signatures, authentication, and distributed capabilities, moving beyond mere secrecy to ensure the integrity of electronic documents. Modern applications, however, still grapple with the same fundamental vulnerabilities as their ancient predecessors. The 2021 Operation Trojan Shield, where the FBI operated the 'secure' ANOM messaging app to collect 27 million messages, demonstrates that even the most sophisticated encryption is only as secure as the platform hosting it. Today, cryptography remains a vital, ever-evolving mechanism for managing trust in a world where the volume of data continues to expand at an exponential rate.

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