Advanced Encryption Standard Explained: What It Is and Why You Should Use It

One of the most popular encryption methods worldwide is Advanced Encryption Standard (AES). It ensures privacy and security in everything from cloud storage to online banking by shielding private information from unwanted access. AES’s definition, operation, and importance for both individuals and corporations are covered in this tutorial.

Table of Contents

What is AES
How AES Works
Advantages of using AES
Where AES is commonly used
Implementing AES safely

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What is AES

One of the most used encryption techniques worldwide is the Advanced Encryption Standard (AES). Since it is a symmetric key encryption scheme, data is encrypted and decrypted using the same key. The U.S. National Institute of Standards and Technology (NIST) formally adopted AES in 2001 as a replacement for the outdated Data Encryption Standard (DES), which was now susceptible to brute-force attacks.

Definition and purpose

AES is designed to protect sensitive information by transforming plain text (readable data) into ciphertext (unreadable code).
Only someone with the correct encryption key can reverse the process and access the original data.
Its main purpose is to ensure confidentiality, integrity, and security of electronic communications, files, and transactions.

A standard trusted worldwide

AES is approved for securing top-secret U.S. government data.
It has become the global encryption standard for protecting financial transactions, personal communications, cloud storage, Wi-Fi networks, and more.
Because of its speed and efficiency, AES is widely used in both hardware (like secure chips and mobile devices) and software (such as messaging apps, VPNs, and file encryption tools).

How AES Works

AES is powerful not only because of its strength but also because of its simplicity and speed. Let’s break down the main elements that make AES such an effective encryption standard:

Symmetric encryption basics

AES is a symmetric encryption algorithm, which means the same secret key is used to both encrypt (lock) and decrypt (unlock) data.
Unlike asymmetric encryption (which uses a public/private key pair), symmetric encryption is faster and more efficient, making it ideal for securing large volumes of data such as databases, file storage, and internet traffic.

Key sizes and strength

AES supports three standard key lengths:

AES-128 → Uses a 128-bit key, strong enough for most applications.
AES-192 → Uses a 192-bit key, offering even greater security.
AES-256 → Uses a 256-bit key, considered military-grade encryption.

Security tradeoff:

A higher key size means more rounds of encryption, making it harder for hackers to crack.
However, longer keys require slightly more processing power, though the slowdown is negligible on modern devices.

Encryption process

AES encryption isn’t just about scrambling data randomly. It follows a well-defined process:

Data is divided into blocks → AES always works with fixed-size blocks of 128 bits (16 bytes).

Rounds of transformations → Depending on the key size, AES applies multiple rounds of mathematical transformations:

AES-128 → 10 rounds
AES-192 → 12 rounds
AES-256 → 14 rounds

Each round includes:

Substitution (SubBytes): Bytes are replaced with values from a substitution box (S-box) to add confusion.
Permutation (ShiftRows): Data bytes are rearranged for diffusion.
MixColumns: Columns of data are mixed to increase complexity.
AddRoundKey: A round key (derived from the original secret key) is combined with the data.

After all rounds, the output is ciphertext, which appears as random gibberish without the key.

Advantages of using AES

AES has become the gold standard in encryption for a reason—it combines strong security, excellent performance, and universal trust. Here’s why it stands out:

Strong security

Resistant to known attacks: AES is designed to withstand brute-force attempts and cryptographic attacks, making it one of the most reliable encryption standards available.
Military and government trust: It is the encryption standard approved by the U.S. National Institute of Standards and Technology (NIST) and is widely used by government agencies, including the NSA, to protect classified information.
Protects all types of sensitive data: From personal information (like passwords and health records) to financial data (such as online transactions) and corporate secrets, AES provides a security foundation that instills confidence.

Performance

Optimized for modern hardware: AES is extremely efficient on today’s processors, many of which include built-in AES instructions (AES-NI) to accelerate encryption and decryption.
Handles large data quickly: Its block-based design allows AES to process gigabytes of data per second, which is crucial for applications such as VPNs, cloud storage, and secure file sharing.
Supports real-time use: Whether it’s encrypting messages in apps like WhatsApp or securing video streams, AES operates fast enough to keep everything seamless and lag-free.

Wide adoption

Global standard: AES is used worldwide across industries, which means it has been extensively tested, verified, and trusted.
Adopted by top organizations: Banks, hospitals, cloud storage providers, messaging apps, and governments all rely on AES to protect sensitive communications.
Cross-platform compatibility: Because AES is so widely implemented, encrypted data can be securely shared across different devices, systems, and services without compatibility issues.

Where AES is commonly used

AES powers a large portion of the digital security we use on a daily basis, therefore it’s not just a theoretical standard. AES is essential to data security for anything from the information on your laptop to the websites you browse. The following are the most typical uses:

Data storage and file encryption

Hard drives and SSDs: Many laptops and desktops use AES-based encryption (like BitLocker or FileVault) to secure the entire drive, preventing unauthorized access if the device is stolen.
USB drives and external storage: Portable storage devices often use AES encryption to protect sensitive files during travel.
Cloud storage services: Providers such as Google Drive, Dropbox, and OneDrive rely on AES to encrypt files stored in the cloud, ensuring your personal or business documents are secure.

Online communications

HTTPS websites: Every time you see a padlock in your browser, AES is working in the background as part of the SSL/TLS protocol to encrypt data between your device and the website.
VPNs (Virtual Private Networks): VPN services use AES to encrypt your internet traffic, keeping your browsing activity private from hackers and ISPs.
Secure messaging apps: Platforms like WhatsApp, Signal, and Telegram implement AES in combination with other encryption methods to keep chats and calls confidential.

Financial transactions

Credit card payments: AES ensures that card numbers and personal details are safely transmitted during online shopping.
Online banking: Banks use AES to protect login details, transaction history, and account data.

Cryptocurrency wallets: AES is commonly integrated into wallet software to secure private keys, which are essential for accessing and sending crypto assets.

Implementing AES safely

Although AES is among the most secure encryption technologies out now, how well it works relies on how it is used. Outdated software, bad storage habits, or weak keys can compromise even the most robust encryption. Use these best practices to get the most out of AES:

Use strong, unique keys

Avoid predictable keys: Simple passwords like 123456 or password make AES encryption useless. Attackers can brute-force weak keys easily.
Never reuse keys: Using the same encryption key across multiple files, devices, or applications increases the risk of exposure.
Use a password manager: Tools like 1Password, Bitwarden, or LastPass can generate and securely store long, random keys that are virtually impossible to guess.

Combine with other security measures

Two-factor authentication (2FA): Even if someone gets your encrypted data, they still need the second factor (like a code from your phone) to access accounts.
Firewalls and secure networks: AES can protect your data in transit, but using it over an insecure Wi-Fi network can still expose you to risks. Always use trusted connections.
Layered security: Pairing AES with other defenses (VPNs, antivirus, intrusion detection systems) creates a multi-layered shield against threats.