What does cryptography mean?
Cryptography is the science and practice of securing information by transforming it into a form that can be read only by those who possess the correct key. Derived from the Greek words kryptos (hidden) and graphein (writing), the term literally means 'hidden writing.' Historically associated with military codes and diplomatic ciphers, cryptography has become foundational to modern life: it protects online banking, encrypts messaging apps, verifies software updates, and secures digital currencies. The field encompasses both symmetric systems, where sender and receiver share a secret key, and asymmetric or public-key systems, which underpin most internet security today. Closely allied but distinct is cryptology, the parent discipline that also includes cryptanalysis, the art of breaking codes. Cryptography carries connotations of secrecy, trust, and mathematical rigour, and its practitioners are called cryptographers. As digital threats grow, understanding cryptography has shifted from a specialist concern to a matter of broad public relevance.
nounThe practice and study of techniques for secure communication, in which information is encoded so that only intended recipients can read it. More broadly, the science of protecting data through encryption and related methods.
- The science and practice of encoding information so that it can be read only by authorized parties; encryption techniques used to protect data in transit or at rest.
- The broader field of study concerned with secure communication techniques, including key exchange, digital signatures, and authentication.
"Modern banking relies on cryptography to keep transactions secure."
"Strong public-key cryptography underpins virtually every secure website on the internet."
"During the war, breakthroughs in cryptography at Bletchley Park gave the Allies a decisive intelligence advantage."
As an academic and technical field, cryptography is normally treated as uncountable and has no standard plural form.
"Cryptography plays a central role in modern cybersecurity."
Cryptography once decided the fate of nations — Alan Turing's codebreakers shortened World War II by an estimated two years — and today it quietly guards every message you send.
Reviewed by Deb Chak, Editor. AI-assisted content curated by RJS Tech Solutions LLP.
Etymology of cryptography
Cryptography derives from the ancient Greek words kryptos, meaning 'hidden,' and graphein, meaning 'to write,' giving the literal sense of 'hidden writing.' The term entered English usage in the mid-seventeenth century, though the practice of secret writing dates back thousands of years to ancient Egypt, Greece, and Rome. It shares this Greek root with related terms such as cryptic, encrypt, cryptogram, and steganography, all built around the idea of concealment. The modern scientific sense of the word expanded dramatically with twentieth-century advances in mathematical encryption.
Related word forms
How cryptography is actually used
Formal to technical register; common in computing, security, and mathematics contexts. Often treated as an uncountable field of study, though occasionally used with an indefinite article when referring to a specific method or system. In everyday speech, 'encryption' is more common for the general concept.
Easily confused with cryptography
Cryptology is the umbrella field encompassing both cryptography (making codes) and cryptanalysis (breaking them), while cryptography strictly refers to designing and using codes.
Steganography hides the existence of a message entirely, whereas cryptography scrambles a message's content so it is unreadable without a key.