AES encryption is a symmetric encryption standard used to protect data by converting readable information into unreadable ciphertext using a secret key.
The name stands for Advanced Encryption Standard, a cryptographic system adopted as an international standard for securing digital communication and stored data. Symmetric encryption means the same key is used to encrypt and decrypt the information, so both the sender and the receiver must have access to the same secret key for the data to be read.
AES replaced older encryption methods, such as DES, because they no longer provided enough protection against modern computing power.
Today, this encryption protocol is used across operating systems, wireless networks, and secure internet connections where information must remain private while it is being transmitted or stored.
How AES encryption works
It operates as a block cypher, meaning it processes data in fixed-size blocks rather than encrypting one character at a time. Each block undergoes a series of mathematical transformations designed to obscure the original content and make the output unintelligible without the correct key.
AES supports key sizes of 128, 192, and 256 bits, and the key length determines how many rounds of transformation are applied during encryption. Longer keys require more rounds, which makes the encrypted data harder to break using brute-force methods.
Because AES uses the same key for encryption and decryption, the key must be securely shared between the communicating systems. When encrypted data is transmitted across the internet, it still travels between devices using an IP address, but the information inside the packets cannot be read without the shared key.
During each round, the algorithm performs substitution, shifting, and mixing operations that change the data in a predictable way for authorized users but appear random to anyone without the key.
Why AES encryption is used
AES is widely used because it provides strong protection while remaining fast enough for everyday network traffic. Modern internet activity involves constant data exchange between devices, servers, and online services, and that data often passes through networks that are not private.
Encryption prevents the information from being read if it is intercepted while travelling between systems. Secure websites, messaging services, wireless networks, and virtual private network connections all rely on AES to protect login details, personal data, and files in transit.
Encryption is also used when data is stored on a device, so that the contents cannot be accessed without the correct credentials. In many secure connections, AES works together with an encryption protocol to create a protected channel between the user and the remote server, allowing information to travel safely across public infrastructure.
Where AES encryption is used
AES encryption is built into many technologies that handle sensitive information, which is why most users rely on it without noticing it. It’s commonly used in systems that protect data as it moves across networks and often forms part of secure communication methods such as End-to-End Encryption (E2EE).
You will often find AES in the following technologies:
- HTTPS connections using Transport Layer Security (TLS), where data sent between a browser and a website is encrypted
- VPN connections that encrypt traffic between a device and a remote server while it travels across the internet
- Wi-Fi security standards such as WPA2 and WPA3 that protect wireless network traffic from nearby devices
- Operating system disk encryption is used to secure stored files, drives, and backups
Cloud storage platforms and enterprise servers that protect information and prevent data breaches both during transfer and while it remains stored
Because AES is efficient and widely supported, it has become the default encryption method across most modern security systems, where it is often combined with an encryption protocol to create a secure communication channel.