A look at historical ciphers, from the Spartan 'scytale' to the Navajo Code Talkers

The science of cryptography, including methods to encrypt data and how to break encryption

Monoalphabetic ciphers use a set of rules to replace each letter with another consistently, making them susceptible to brute force attacks that try every kind of replacement. While more complex ciphers can transform text in less obvious ways, because certain letters are used more often than others, an analysis of letter frequency may reveal patterns that help uncover the rules that make up a cipher.

The story of Kryptos, the long unsolved cryptographic sculpture outside the CIA's headquarters

Made by American artist Jim Sanborn, the sculpture features four copper plates engraved with messages written with the 26 letters of the Latin alphabet and question marks. The last of these plates was solved in 2025, but the piece remains of interest to cryptoanalysts.

Practice encrypting and decrypting text using an online library of ciphers

This tool provides users with customizable protocols, including Caesar, Affine, and Vigenère ciphers, to hide messages in transformed text and convert them back into legible formats. Mechanisms are also available to convert text into other communication languages, such as Morse code and URL encoding.

The history and operation of SIGABA, the US counterpart of the Nazi Enigma machine

Developed by the US Army and US Navy, over 10,000 of these machines were deployed by the end of World War II to encrypt messages for the armed forces using three series of rotors. The device would continue to be used until the 1950s, while personal computers were shown to possess enough computing power to crack it by 2021.

Claude Shannon, for whom Anthropic's AI tools are named, proved the existence of an unbreakable cipher

In the one-time pad approach, the encryption key is randomly generated and of equal length to the plaintext. This randomness ensures that every possible plaintext is equally likely—RBBHN can mean HELLO, SOLVE, CODES, and so on, using a different key—while matching the message and key lengths prevents the appearance of patterns that can be exploited.

Archaeologists decode the first known sentence in what may be the oldest written alphabet

This five-minute video details the accidental discovery and subsequent decoding of the first known sentence in what's believed to be the oldest written alphabet. The Canaanite sentence was found on a Bronze Age hair comb unearthed in Tel Lachish, a city of the ancient Biblical Kingdom of Judah, during a dig focused on excavating the kingdom's first Iron Age city. The Canaanite language developed sometime between 3,000 and 1,000 BCE.

Watch how the Enigma machine encrypts messages and learn about its critical design flaw

Using settings selected from a series of rotors and a plugboard that let operators swap letters with any of their choosing, the machine lit up the output letter for each letter typed. While this system could generate messages requiring any of 150 quintillion potential keys, the machine's reflector never encrypted a letter as itself, providing an entry point for exploiting the system.

Jacqueline Jenkins-Nye—Bill Nye's mother—worked as a code-breaker in World War II

While in the Navy, she was recruited to work on Enigma to help decode messages from the German military. Historians estimate that the efforts of code-breakers may have collectively shortened the war by as much as two years.

How the Inca used threads to communicate

One of the great mysteries of ancient Peru is that the Inca did not have a system of writing, but communicated with a system of strings tied with knots. This 4-minute video explores its possible uses.

A collection of ancient Mayan glyphs and pictographs

The Maya had a syllabic and pictorial writing style that featured many incredibly detailed glyphs. Click here to check out this ancient writing style (and maybe test out their related phonetic sounds).

In 1822, French scholar Jean-François Champollion deciphered Egyptian hieroglyphs using the Rosetta Stone.

Cacao is a Maya word that survives today

In the 1980s, archaeologists finally deciphered Maya hieroglyphs in part by identifying known words. Maya scholar David Stuart notes that cacao—still used today—was one of the key linguistic anchors that unlocked ancient Maya texts.

The long-lost art of coded postage stamps

In the 1800s, the postcard was a relatively new phenomenon, as was the post office. In the burgeoning system, recipients of mail had to sometimes pay prohibitively costly fees to receive it. So to get around the fees, a system of placing stamps on the envelopes in specific ways to communicate—a simple yes or no—was devised by clever mailers and expanded and codified by postcard companies into guides. Learn about the fascinating system here.

Create your own cipher by combining mathematical operations and encryption protocols

This tool allows users to build an encryption workflow in which the output of one customizable function becomes the input to another, thereby creating undiscovered methods for obscuring information via a series of ciphers.

Ready to try reading some Maya hieroglyphics?

The Mayan hieroglyphic script was the only true writing system developed in the Americas prior to European colonization. Examples of the millennia-old script have been discovered on stone pillars, pottery, and texts known as codices. Here’s a Maya writing system study guide for the high achievers among us.

Indigenous women crafted the integrated circuits for the Apollo Guidance Computer

Applying their blanket-weaving skills, over 1,000 Navajo women in New Mexico were hired to connect circuit components in intricate patterns using a microscope. Outside Boston, "rope mothers" at the Raytheon facility wove the AGC's core memory using threaded metal wires.

View how AES—the global standard for symmetric encryption—works

Established by the National Institute of Standards and Technology in 2001, the Advanced Encryption Standard transforms plaintext into ciphertext using multiple rounds of processing, including substitution, transposition, and mixing. Larger keys undergo more rounds to produce 16-byte blocks of scrambled data, with 256-bit AES keys taking 3.31 × 10⁵⁶ years to decrypt via brute force.

Explore different ways the ancient Greeks laid the foundation of Western culture, from philosophy to sports (w/quiz).

Medieval sword manuals survive—but their techniques are hard to decode

While some knights guarded their combat knowledge, others recorded it in illustrated fighting manuals. Centuries later, scholars struggle to interpret these cryptic texts, revealing how much medieval martial knowledge was lost or obscured over time.

A US Department of Defense research lab developed the technology for the dark web

Although encryption existed to mask the content of communications across the internet before the 1990s, those managing overseas network infrastructure could determine a spy's affiliation based on where they saw data sent to and received from. To keep this information secret, the US Naval Research Laboratory developed onion routing, which enabled anonymized web browsing. The release of the technology to the public obscured sensitive communications further by growing the volume of anonymous data.

Sequoyah single-handedly invented a writing system for the Cherokee language

Without formal education, Cherokee citizen Sequoyah spent more than a decade in the early 1800s developing an 86-character syllabary—a writing system in which each symbol represents a spoken syllable—for the Cherokee language. Within a few years, most Cherokees could read and write it.

Ancient Romans sometimes lobbed insults through graffiti

Graffiti was used to communicate ideas, offer advice, and, not unlike the internet, talk some trash. That was especially true with tourists, who sometimes scrawled messages on the pyramids, including one person who complained, "I can not read the hierogylphics." In response, someone replied, "Why do you care that you can not read the hieroglyphics? I do not understand your concern."

Ancient ghost stories appeared in texts like 'The Odyssey'

Sharing ghost tales has been around for centuries. Ancient Mesopotamia, Rome, and Greece each had their own chilling stories about encountering spirits. Find mentions of specters in some of history’s most famous writings like the "Epic of Gilgamesh" and "The Odyssey."

Using AI to rewrite and revive Aztec tales

Despite being vanquished by the conquering Spaniards in the 16th century, the Aztecs' culture endured through their descendants and rituals, as well as texts that escaped destruction at the hands of the Europeans. These texts, known as codices and preserved in part by Christian monks, revealed intimate details of life as an Aztec in the Middle Ages. Today, AI programs allow students to learn the Aztec's language, Nahuatl, further preserving their heritage.

Unraveling the charred remains of the only known library from antiquity

This article details the quest to decipher the charred remains of a library buried during Mt. Vesuvius' volcanic blast. In 1752, nearly 2,000 papyrus scrolls were found in Herculaneum. According to this article, this collection is the only complete library that has survived from antiquity. In the last decade, scientists have made strides in decoding the crumbling texts.

A visual guide to how bitcoin transactions work and rely on cryptography

The "crypto-" in cryptocurrencies like bitcoin refers to the mathematical functions that generate pairs of public and private keys and encrypt data in blocks. When combined, these systems secure transactions on the network, verify digital asset and token transfers, and contribute to end-user anonymity.

The Greeks named their dogs with short names similar to modern ones.

Chess traces its roots to chaturanga in sixth-century India

The earliest form of chess, known as chaturanga, emerged in India around the sixth century. The game simulated four divisions of the military—infantry, cavalry, elephants, and chariots—and laid the foundation for modern chess’ structure and strategy.

The Antikythera mechanism: The oldest-known analog computer

A device now considered the world's oldest computer was pulled from a shipwreck more than 120 years ago. Known as the "Antikythera Mechanism," it is now believed to have allowed precise tracking of astronomical positions, and its sophistication overturned understanding of Ancient Greek capabilities.

Hear what ancient Greek music sounded like.

Maya writing was the first actual script in the Americas

The ancient Maya developed the Americas’ earliest complete writing system, which was preserved on ceramics, stone, textiles, shells, and in surviving texts. Though much was destroyed, the remaining artifacts offer a rare insight into Maya literary culture through a virtual tour

The warrior women of Ancient Scythia who inspired the Greek Amazons

Greek literature regales readers with tales of Amazon queens and warriors going toe-to-toe with heroes, including Achilles and Hercules. This article explores why these female warriors were relegated to myth. For a long while, it was believed that these stories about all-female warriors were just stories. But scientists have since found evidence that these ancient warriors were part of the nomadic tribes of Scythia, and more discoveries are expected.

A reading of ancient Rome's best graffiti

Graffiti has been surprisingly common throughout history, and even the grandeur of ancient Rome's walls wasn't spared. This clever and funny video reads through some of the more notable messages relayed via graffiti in ancient Rome, from tidbits of wisdom like "A small problem gets larger if you ignore it" to more unsavory observations of lovers, friends, and enemies.

Pre-coin currencies like shells were subject to counterfeiting

While it is difficult to pinpoint the very earliest form of money that was used, a type of shell called cowrie shells were used as currency as far back as 3300–2000 BCE. These shells were imitated using ivory, bone, clam shells and more.

Ancient Romans helped develop modern cheese production techniques

The ancient Romans loved cheese and experimented with different processes to elevate its flavor, like aging. Some of their innovations, like Pecorino Romano, you can still find today. Others, like the smoked goat-milk Caseus, we only know about through historical records.

Contactless credit cards descend from a batteryless Cold War listening device

The same physics that let Soviet spies eavesdrop on the US ambassador in 1945 underlie contactless payment methods today. The device is a passive chip powered wirelessly by incoming radio waves.

The land where Greece's ancient language survives

In a remote corner of Turkey, locals speak Romeyka, a language with no written form and an "impressive" similarity to ancient Greek. This article details how the language may have survived and highlights the roughly 5,000 Romeyka speakers in the area. Research shows that Romeyka bears a startling resemblance to the Koine Greek spoken at the height of ancient Greek influence between fourth century BCE and fourth century CE.

The first compiler to facilitate communication with computers was developed by Grace Hopper

The A-0 program linker automatically translated mathematical symbols into machine-readable binary code. Although it took two years for computer executives to get on board with the idea, the technology was foundational to future programming languages that allowed computers to understand commands written in word-based languages.

Tattoos were once used to identify status

Around 450 BCE, Scythians inhabiting what is now southern Siberia were recorded as wearing tattoos of swirling mythical beasts to signify nobility. At the same time, tattoos have identified lower-status and enslaved people.

Memes can be traced back to the chain letter

Such intentional reshaping of communication transmissions dates back at least hundreds of years to the advent of the chain letter, a type of message that asks readers to create their own copy or at least forward it to others.

Internet sleuths solve secret message on Perseverance rover’s Mars parachute

In 2020, the Perseverance Rover landed on Mars, sending a message for the folks back home on its parachute. It took fewer than six hours for the Internet's collective forces to decode the secret slogan hidden in the parachute's colors and patterns, as well as the geographic coordinates of the earth-bound place where rocketry was perfected.

Visualize how passkeys, which rely on asymmetric cryptography to authenticate users, work

After using biometrics or a PIN to access the private key stored on a device, it is combined with a random number generated by the site to produce a cryptographic signature. This signature is verified using the site's public key, allowing a user to log in without entering a password. This reduces the risk of fraudulent messages—phishing attacks—and data breaches.

How end-to-end encryption protects messages, even from service providers

Using symmetric and asymmetric cryptography, data is encrypted on the sender's device before being transmitted across application servers that lack the key needed to decrypt it. The message is not decrypted until it reaches the recipient's device, which uses their private key to recover the plaintext. E2EE's effectiveness has led to its adoption by WhatsApp and Signal.

Abaci, the plural of abacus, allowed individuals to perform arithmetic and tally quantities by moving pebbles called calculi, from which the word 'calculator' is derived.

DNA cassette tapes could store 36,000 terabytes of data

By translating binary code into the base-pair code found in genetic sequences, researchers in China are storing digital data on DNA-coated tapes for compact, durable, and energy-efficient storage. The tapes use a blend of polyester and nylon with barcode patterns for data addressing.

A timeline of how Claude Code was used to execute cyberespionage

In September 2025, a Chinese state-sponsored group targeted 30 large tech companies, financial institutions, chemical manufacturing companies, and government agencies by manipulating Claude Code, having succeeded in infiltrating a small subset. The cyberattack is believed to have been the first of its scale carried out without major human intervention.

Medieval monasteries preserved ancient knowledge through hand-copied books

Medieval monks and nuns lived in religious communities devoted to work and prayer. Still, their script-copying traditions had a lasting impact: through illuminated manuscripts, monasteries preserved hundreds of ancient texts that might have otherwise been lost.

The Ishango bone suggests mathematics was born about 20,000 years ago

Ancient civilizations developed mathematical systems for various purposes, including the Egyptians for the construction of the pyramids and the Ancient Greeks for logical reasoning in theorems. However, these systems were predated by the Ishango bone—found in the Democratic Republic of the Congo—whose notches suggest a base ten system, prime numbers, and simple mathematical operations.

From bartering to banking, temples to electronic transactions, here’s banking has evolved significantly since ancient times

A few historical facts about banking (like that one day, not long ago, certificates of deposit were physical pieces of paper) may not surprise you. But did you know that the church was the original lender? And that Julius Caesar himself invented foreclosure?

Crypto's origins date back to 1983

While crypto feels new, it actually dates to 1983, with eCash's creation. However, a lot has happened in the crypto world over the past few years in particular—crypto's market cap surpassed $2T for the first time in 2021, for instance. A timeline of crypto's history details the events in between.