Derived from the Greek words for “hidden writing,” cryptography is the science of obscuring transmitted information so that only the intended recipient can interpret it. Since ancient times, the practice of sending secret messages has been common across almost all major civilizations. Cryptography is now a critical aspect of cybersecurity, protecting digital privacy by securing everyday personal messages, authenticating digital signatures, and safeguarding payment information for online shopping, as well as top-secret government data and communications

Although the practice dates back thousands of years, cryptography and its broader field, cryptanalysis, are still considered relatively young, having made tremendous advancements in only the last 100 years. With the invention of modern computing, the dawn of the digital age also heralded the birth of modern cryptography. As a critical means of establishing digital trust, mathematicians, computer scientists, and cryptographers began developing modern cryptographic techniques and cryptosystems to protect critical user data from hackers, cybercriminals, and prying eyes.

Most cryptosystems begin with an unencrypted message known as plaintext, which is then encrypted into an indecipherable code known as ciphertext using one or more encryption keys. This ciphertext is then transmitted to a recipient. If the encryption algorithm is strong, the ciphertext will be useless to any unauthorized eavesdroppers because they won’t be able to break the code. The intended recipient, however, will be able to decipher the text with the correct decryption key.

Here’s a look back at the history and evolution of cryptography:

Ancient Cryptography:

– 1900 BC: Hieroglyphs carved into the wall of a tomb from the Old Kingdom of Egypt were one of the first implementations of cryptography.
– 1500 BC: Clay tablets found in Mesopotamia contained enciphered writing believed to be secret recipes for ceramic glazes.
– 650 BC: Ancient Spartans used an early transposition cipher to scramble the order of letters in military communications.

Medieval Cryptography:

– 800: Arab mathematician Al-Kindi invented the frequency analysis technique for cipher breaking.
– 1467: Leon Battista Alberti’s work explored the use of ciphers incorporating multiple alphabets.
– 1500: Giovan Battista Bellaso published the Vigenère Cipher, considered the landmark polyphonic cipher of the 16th century.

Modern Cryptography:

– 1913: The outbreak of World War I led to a steep increase in cryptology and cryptanalysis for military communications.
– 1917: American Edward Hebern created the first cryptography rotor machine to automatically scramble messages.
– 1918: German cryptologist Arthur Scherbius developed the Enigma Machine, used heavily by the Germans during WWII.
– 1975: IBM developed the Data Encryption Standard (DES), the first cryptosystem certified by the National Institute for Standards and Technology (NIST).
– 1976: Researchers Whitfield Hellman and Martin Diffie introduced the Diffie-Hellman key exchange method for securely sharing cryptographic keys.
– 1977: Ron Rivest, Adi Shamir and Leonard Adleman introduced the RSA public key cryptosystem.
– 2001: The DES was replaced by the more robust Advanced Encryption Standard (AES) encryption algorithm.

Quantum Cryptography and the Future of Encryption:

The field of cryptography continues to evolve to keep pace with advancing technology and increasingly more sophisticated cyberattacks. Quantum cryptography and post-quantum cryptography are two areas at the forefront of this evolution. Quantum cryptography uses the immutable laws of quantum mechanics for data encryption, while post-quantum cryptographic algorithms use different mathematical cryptography to create quantum computer-proof encryption. Both have the potential to revolutionize data security in the digital age.