What is Cryptography? 

Cryptography is the study of the methods of hiding information to protect it from unauthorized access.  Cryptographic functions are a critical element of modern cybersecurity and are used to protect data from malicious actors. Cryptographic techniques can secure any digital content—texts, images, videos, or audio.   

A common form of cryptographic use is encryption, which turns messages into secret codes (called ciphertext) that can only be unlocked with a special decryption key. Cryptography has been around since ancient times, and its name comes from the Greek “kryptos,” meaning “hidden.” One of the first examples is ”Caesar’s Cipher” used by Julius Caesar around 58 BC, that shifted letters in a message to render it unreadable should it be intercepted.   

The Principles of Cryptography 

From its ancient roots, modern cryptography has become much more advanced, but it still follows four basic principles:  

1. Confidentiality – Only the intended person can read the information. 
2. Integrity – The information can’t be changed without it being noticed. 
3. Non-repudiation – The sender can’t deny that they sent the information. 
4. AuthenticationWhat is Authentication? Authentication is the process by which the identity of a user or system is verified. It ensures that the entity attempting to access a resource is who… More – Both the sender and receiver are verified, and the origin and destination of the information are confirmed. 

 How is Cryptography Used? 

 There are many common ways in which cryptography is used:  

1. Passwords – Cryptography helps check if passwords are correct without storing them in plain text, making them harder for threat actors to steal. 
2. Cryptocurrency – Digital currencies like Bitcoin and Ethereum use cryptography to create new coins, secure wallets, verify transactions, and prevent fraud. 
3. Secure web browsing – Cryptography keeps websites safe from cyber criminals and spying by using protocols like Secure Socket Layer (SSL) and Transport Layer Security (TLS)What is Transport Layer Security (TLS)?  Transport Layer Security (TLS) is a commonly used cryptographic protocol for secure data transmission across networks. Whether a user is logging into a website,… More to protect data shared between the browser and the websites it visits. 
4. Electronic signatures – Online signatures (e-signatures) use cryptography to prove they are real and prevent tampering or forgery. 
5. Authentication – Cryptography verifies who an individual is when they login to services like online banking or secure networks. 
6. Secure communications – End-to-end encryptionWhat is Encryption? Encryption converts readable data (plaintext) into a scrambled and unreadable format (ciphertext) using an algorithm and a key. The primary purpose of encryption is to ensure the… More protects private conversations, including chats, emails, and video calls, so only the sender and receiver can read them. Apps like WhatsApp and Signal use this to keep messages safe.  

Cryptographic Keys and Key Management  

Cryptographic keys can be thought of as secret codes used to lock and unlock encrypted information. Managing these keys — creating, sharing, storing, and replacing them — is a critical and complex part of keeping data safe. 

 One popular method to share keys securely over the internet is the Diffie-Hellman key exchange, another is asymmetric key cryptography. Modern cryptographic keys can be 128, 256, or even 2,048 bits long, and these bits are used to scramble data in ways that are nearly impossible to guess. 

For instance: 

 A 56-bit key could be broken in about 13 minutes. 

• A 128-bit key would take about 1.872 x 10³⁷ years. 

• A 256-bit key would take about 3.31 x 10⁵⁶ years. 

 If a bad actor tried to break a simple cipher, they could quickly try every possible combination — this is called a brute force attack. But with longer keys, brute force attacks would take much longer. However, there is the fear that quantum computers will soon be able to break even the strongest encryption methods that are used to secure information today.  

The Future of Cryptography  

Fortunately, cryptography is evolving to keep up with the quantum threat. New methods include quantum cryptography, lattice-based cryptography, and Elliptic Curve Cryptography (ECC). 

Elliptic Curve Cryptography (ECC): ECC is an advanced encryption method that creates smaller, faster, and more efficient cryptographic keys compared to older systems. Unlike traditional methods, ECC uses curved lines (elliptic curves) on a graph to generate keys, making it more efficient, especially for devices with less computing power, like smartphones. Companies like Apple, Bitcoin, and the US government are already using ECC. As quantum computingWhat is Quantum Computing? Quantum computing is a cutting-edge field that leverages the principles of modern physics to perform operations significantly faster than classical computers. Classical computers, including the laptops,… More grows, ECC is expected to become the standard for online security. 

Quantum Cryptography: Quantum cryptography uses the laws of quantum mechanics to secure data in a way that traditional encryption cannot. It sends light particles (photons) across fiber optic cables to share secret keys between the sender and receiver. Because observing quantum data changes it, any attempt to compromise it would be immediately noticed. Although it’s still in its infancy, quantum cryptography promises to be infinitely more secure than traditional systems, preventing eavesdropping and integrating with other encryption methods. 

Lattice-based Cryptography: Lattice-based cryptography uses grids of points in multiple dimensions for encryption, providing a way to protect data against quantum computers. 

For more essential cybersecurity definitions, check out our glossary here.