암호학의 역사

Cryptography started well before the internet. This practice of communicating using secret code dates back to ancient times, as scribes, rulers, and generals alike used secret scripts to protect messages from prying eyes.

Today, the same principles help secure everything from your bank account to classified government data. Cryptography has become an invaluable component of modern computing.

This article explores the history of cryptography and how it’s evolved throughout the ages, advancing from primitive ciphers to the algorithms that drive global cybersecurity today. We’ll also peek ahead at what’s next. Post-quantum threats and cryptographic shifts are already well underway.

• Cryptography dates to ancient times and was also used in the medieval and Renaissance eras.
• World War II marked a turning point in cryptography history with the invention of the Enigma machine and its eventual decryption.
• Growing computer power rendered the Data Encryption Standard (DES) of the late 20th century obsolete, leading to the adoption of stronger algorithms like the Advanced Encryption Standard (AES).
• Quantum computing’s rise is pushing the frontiers in cryptography, as researchers design new models to keep data safe.

Cryptography is the science of securing communications and data by encoding it such that only authorized parties can read it.

You may have read in mystery novels about spies and detectives hiding a cipher in a book or using invisible ink. Today, data encryption is far more sophisticated. It uses advanced algorithms and digital keys to protect sensitive or confidential information from unauthorized parties across a variety of applications, from protecting classified government information to generating computer passwords.

As threats evolve and the potential of quantum computing grows, cryptography will become increasingly indispensable to organizations seeking to shield their data from cyberattacks.

While it’s impossible to pinpoint precisely when cryptography was invented, its earliest instances trace back to antiquity.

Mesopotamia (~1500 B.C.): A clay tablet from this era hides a recipe for ceramic glazes beneath enciphered writing, one of the earliest examples of protecting intellectual property.

Sparta (~650 B.C.): Spartans encoded military messages on leather strips, which could only be read when wrapped around a matching stick called a scytale. The system depended on using the correct diameter for decoding.

Ancient Rome (~100 B.C.): Julius Caesar used a simple shift cipher, replacing each letter with one a few positions away in the alphabet, an early use of cryptography for personal and sensitive communication.

Medieval Arabia (~800s A.D.): Arab scholar Al-Kindi developed frequency analysis, studying symbol frequency to make educated guesses about plaintext. It was the first structured codebreaking method and a major leap in cryptography.

Renaissance Europe (~1500s A.D.): Italian cryptographer Giovan Battista Bellaso introduced the polyalphabetic cipher (later misattributed to Blaise de Vigenère). It remained unbroken for 300 years, until Friedrich Kasiski cracked it in 1863 using pattern recognition and analysis.

The 20th century marked a transformative era in cryptography history, transitioning from mechanical devices to foundational digital security concepts.

Early 1900s: In 1917, American inventor Edward Hebern combined electrical circuits with typewriter parts to create the first rotor-based encryption machine. He began developing the idea while in prison for horse theft. His machine let users type a message, which it encrypted automatically. To decode, users reversed the rotor and retyped the ciphertext.

World War II: After WWI, German cryptologist Arthur Scherbius expanded on Hebern’s concept and built the Enigma Machine. The Germans used it in WWII for top-secret messages, which required precise calibration and keys to decode.

The effort to break Enigma became legendary. Under Alan Turing’s leadership, British codebreakers, along with Polish cryptanalysts who had fled the Nazis, built a machine that decrypted Enigma messages. This was a major turning point for the Allies. 

Late-century advances: In the 1970s, a new kind of encryption emerged using asymmetric keys. It improved privacy by removing the need for a shared key. Messages were encrypted with a public key and decrypted using a private one.

This led to the development of public key infrastructure (PKI). PKI encompasses the roles, policies, hardware, software, and processes needed to manage digital certificates and public key encryption. PKI supports secure electronic transmission of data for everything from email to payments.

In the 1970s, IBM developed the Data Encryption Standard (DES), a symmetric-key algorithm later adopted by the U.S. federal government. It worked well for a time, but as computing power grew, DES became vulnerable to brute-force attacks. In 2001, it was replaced by the Advanced Encryption Standard (AES), which remains a global standard for encrypting bulk data.

The next major leap came with public-key cryptography, which solved a fundamental problem: how to exchange information securely without first sharing a secret. This concept laid the foundation for secure communication over open networks like the internet.

In 1977, cryptographers introduced the RSA algorithm. RSA uses a pair of mathematically linked keys: one public, one private. Messages encrypted with the public key can only be decrypted with the corresponding private key. This innovation allowed for secure key exchange, digital signatures, and the ability to verify identities online, capabilities that are still core to digital security today.

By the 1990s, researchers developed a more efficient alternative: Elliptic Curve Cryptography (ECC). ECC offers the same functionality as RSA, encryption, authentication, and digital signatures, but with much smaller key sizes. This results in faster processing and lower power consumption, which is especially important for mobile devices, IoT systems, and other environments where efficiency matters.

Today, RSA and ECC power a broad range of security functions. They are embedded in TLS (the protocol that secures web traffic), code-signing processes for software and firmware, VPNs, secure email, digital certificates, and more. Their presence is nearly universal across public PKI systems used by enterprises and governments alike.

But this universality also creates risks. Quantum computing threatens the very math that makes RSA and ECC secure. Unlike symmetric algorithms, which can be strengthened with longer keys, public-key algorithms rely on problems like integer factorization and elliptic curve discrete logarithms, problems that quantum computers could solve efficiently. This growing risk is why RSA and ECC now sit at the center of the next major shift in cryptography.

While today's encryption is strong enough to withstand brute-force attacks from classical computers, quantum computing changes the equation. A powerful quantum machine could break the math behind widely used public-key algorithms such as RSA and ECC. This would compromise the security of websites, software updates, digital identities, and other core systems.

That’s why the industry is shifting focus to post-quantum cryptography (PQC).Unlike quantum cryptography, which uses principles of quantum mechanics to securely transmit encryption keys, PQC involves new algorithms that run on classical computers but are designed to resist quantum attacks. The goal is to replace vulnerable algorithms with quantum-safe alternatives before large-scale quantum systems arrive.

This is not a theoretical concern. Cyber attackers are already using "harvest now, decrypt later" tactics, stealing encrypted data today with the intent to decrypt it once quantum capabilities become viable.

To help the world prepare, the National Institute of Standards and Technology (NIST) has released technical standards for three PQC algorithms. These selections represent years of global collaboration and testing. However, implementation is far from simple. 

If this sounds like a routine upgrade, past experience tells a different story. The shift from SHA-1 to SHA-2 took years to complete, and that was just a relatively modest change in hashing algorithms. Some systems still have not fully made the move. The replacement of RSA and ECC will be significantly more complex because it affects authentication, identity, and the foundational trust infrastructure of the internet.

In response, organizations are turning to crypto-agile solutions that support gradual and controlled change. Services like PKI as a Service (PKIaaS) and Hardware Security Modules (HSMs) play a central role. They provide the control and flexibility businesses need to adopt new standards, manage cryptographic keys, and maintain compliance throughout the transition.

Robust cryptographic protection is more crucial than ever. Entrust’s Cryptographic Security Platform was designed to address the growing need for comprehensive cryptographic asset management. Our platform combines PKI and HSM to provide full visibility into your cryptographic keys from a single, cohesive system, delivering unmatched security without the need to manage on-premises hardware or specialized expertise.

As the challenges of digital encryption grow, Entrust is here to provide the flexibility and assurance you need to protect your operations and stay ahead of tomorrow’s security challenges.