AES explained

Advanced Encryption Standard (AES): The Backbone of Secure Data Protection

4 min read Β· Dec. 6, 2023
Table of contents

The Advanced Encryption Standard (AES) is a widely used symmetric encryption algorithm that ensures the confidentiality and integrity of data. In the realm of InfoSec and cybersecurity, AES plays a pivotal role in securing sensitive information and communications across various industries and applications. In this article, we will delve into the intricacies of AES, exploring its origins, technical details, use cases, career prospects, and industry standards.

Origins and Evolution

AES was developed as a replacement for the aging Data Encryption Standard (DES), which had become vulnerable to brute-force attacks due to its relatively short key length. In 1997, the National Institute of Standards and Technology (NIST) initiated a competition, inviting cryptographic experts from around the world to submit encryption algorithms that would be resistant to modern attacks. After a rigorous evaluation process, the Rijndael algorithm, developed by Belgian cryptographers Joan Daemen and Vincent Rijmen, emerged as the winner and was selected as the basis for AES.

Technical Details

AES is a symmetric Encryption algorithm, meaning the same key is used for both encryption and decryption. It operates on fixed-size blocks of data, typically 128 bits, and supports three key sizes: 128, 192, and 256 bits. The larger the key size, the more secure the encryption, but also the higher the computational overhead. AES employs a substitution-permutation network (SPN) structure, utilizing a combination of substitution and permutation operations to ensure the confidentiality and integrity of data.

The algorithm consists of several rounds, with the number of rounds determined by the key size. For AES-128, there are 10 rounds; for AES-192, there are 12 rounds; and for AES-256, there are 14 rounds. Each round consists of four main operations: SubBytes, ShiftRows, MixColumns, and AddRoundKey. These operations collectively provide confusion and diffusion, making it extremely difficult for an attacker to recover the original plaintext from the ciphertext without the correct key.

Use Cases and Industry Relevance

AES is widely used in various domains where secure communication and data protection are paramount. Some notable use cases include:

  1. Secure Communication: AES is commonly used to secure data transmission over networks, such as in Virtual Private Networks (VPNs), Secure Socket Layer/Transport Layer Security (SSL/TLS) protocols, and wireless networks.

  2. Data Storage: AES is employed to encrypt sensitive data stored on devices, such as hard drives, SSDs, and removable media. It ensures that even if the physical storage is compromised, the data remains inaccessible without the encryption key.

  3. Cloud Computing: AES is a fundamental component of securing data in the cloud. It enables organizations to protect their data at rest and in transit, ensuring confidentiality and integrity within cloud environments.

  4. Internet of Things (IoT): With the proliferation of IoT devices, AES is crucial in securing the communication between devices and gateways, protecting sensitive data and ensuring privacy.

The relevance of AES in the industry is evident from its adoption as a standard encryption algorithm by governments, organizations, and security-conscious individuals worldwide. Its robustness and widespread acceptance make it a cornerstone of modern cryptographic systems.

Standards and Best Practices

NIST has published several standards and guidelines related to AES. The most notable ones are:

  • FIPS 197: This standard specifies the requirements for AES and provides detailed technical specifications for its implementation.

  • NIST Special Publication 800-38A: This publication outlines the modes of operation for AES, including Electronic Codebook (ECB), Cipher Block Chaining (CBC), and Counter (CTR) modes, among others.

To ensure the secure implementation of AES, it is crucial to follow best practices, such as:

  • Key Management: Proper key management is vital to the security of AES. Keys should be generated securely, protected from unauthorized access, and periodically rotated to mitigate the risk of compromise.

  • Secure Implementation: Implementing AES in a secure manner requires adherence to coding best practices, regular security Audits, and vulnerability assessments to identify and address potential weaknesses.

  • Cryptographic Module Validation: Organizations that utilize AES should consider using cryptographic modules that have been validated against established standards, such as the FIPS 140-2.

Career Aspects

Professionals with expertise in AES and cryptographic systems are highly sought after in the InfoSec and cybersecurity industry. Some potential career paths and roles in this domain include:

  1. Cryptographer: Cryptographers specialize in designing and analyzing encryption algorithms, including AES, to ensure their security and resilience against attacks.

  2. Security Engineer: Security engineers implement and maintain cryptographic systems, including AES, within organizations, ensuring the confidentiality and integrity of sensitive data.

  3. Penetration Tester: Penetration testers assess the security posture of organizations by attempting to Exploit vulnerabilities, including weaknesses in cryptographic implementations.

  4. Security Consultant: Security consultants provide guidance and expertise to organizations in implementing secure cryptographic systems, including the proper use of AES.

In conclusion, AES is a foundational encryption algorithm that has become the de facto standard for secure data protection. Its robustness, versatility, and widespread adoption make it an essential component of modern cryptographic systems. As the need for secure communication and data protection continues to grow, professionals with expertise in AES and cryptographic systems will play a crucial role in ensuring the confidentiality and integrity of sensitive information.


  1. NIST AES Information
  2. NIST FIPS 197: Advanced Encryption Standard (AES)
  3. NIST SP 800-38A: Recommendation for Block Cipher Modes of Operation
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