AES Encryption Explained: How Advanced Encryption Standard (AES-256) Protects Data, Devices, and Remote Access

With cyber threats on the rise, robust data encryption is essential for keeping sensitive information safe. The Advanced Encryption Standard (AES) has become the go-to choice for industries worldwide, known for its strong security and high efficiency.

AES was standardized by the National Institute of Standards and Technology (NIST) in 2001 to replace the older Data Encryption Standard (DES), which had become vulnerable to modern attacks. After an extensive evaluation process, the Rijndael algorithm was selected for AES because of its strength, efficiency, and flexibility.

Today, AES is considered the gold standard for encrypting sensitive information across industries, from government agencies to financial institutions and technology companies.

In this guide, we’ll cover the fundamentals of AES encryption, explain its advantages, and show how Splashtop uses AES-256 encryption to provide secure, reliable remote access for businesses and individuals.

What is the Advanced Encryption Standard (AES)?

AES Definition

The Advanced Encryption Standard (AES) is a widely used encryption standard designed to protect sensitive data by transforming readable information into a secure, encoded format. AES is a symmetric key encryption method, meaning it uses the same key for both encryption and decryption, helping ensure data remains secure during transmission and storage.

What Is AES Used For?

AES is the backbone of data security in many modern applications. It is used to safeguard data in wireless communications, cloud storage, databases, mobile applications, and more. Thanks to its speed and strong security, AES has become the preferred method for protecting data in a wide range of industries, from healthcare to finance.

How Does AES Encryption Work?

AES encryption converts plaintext into ciphertext using a series of well-defined operations performed over multiple rounds. Here are the key steps:

• Key Expansion: The original encryption key is expanded into a set of round keys using a key schedule algorithm. These round keys are used at each stage of encryption.
• Initial Round – AddRoundKey: The plaintext data is combined with the first round key using a bitwise XOR operation, mixing the key material into the data at the very beginning.
• SubBytes (Byte Substitution): Each byte in the data block is replaced with a corresponding byte from a predefined substitution box (S-box), introducing non-linearity into the cipher.
• ShiftRows (Row Shifting): The rows of the data matrix are cyclically shifted to the left, helping spread byte values across the block and increasing diffusion.
• MixColumns (Column Mixing): Each column of the data matrix is transformed using mathematical operations to further scramble the data and enhance diffusion. (This step is skipped in the final round.)
• AddRoundKey (Key Mixing): Another round key is combined with the data using XOR, tightly binding the encryption process to the secret key.
• Final Round: The final round omits the MixColumns step and completes the encryption with SubBytes, ShiftRows, and a last AddRoundKey operation, producing the ciphertext.

The number of rounds (10, 12, or 14) depends on the key length: 128, 192, or 256 bits, respectively.

3 Types of AES Encryption

AES supports three key lengths—128-bit, 192-bit, and 256-bit—each offering different levels of security and performance:

AES-128 Encryption

This option uses a 128-bit key and is known for its strong balance between speed and security. AES-128 provides robust protection for general data security needs, such as secure file sharing and basic data protection in applications where high speed is important.

AES-192 Encryption

Using a 192-bit key, this version of AES provides a higher security level than AES-128. Although slightly slower, AES-192 is often used in industries that require stronger encryption but want to avoid the full computational overhead of AES-256. It is suitable for secure communications in government or regulated environments.

AES-256 Encryption

The most secure commonly used version of AES, AES-256 uses a 256-bit key and is effectively immune to brute-force attacks with current technology. While it is the most computationally intensive, it is preferred for applications that demand the highest level of security, such as financial transactions, cloud storage, and data backups. AES-256 is widely used in sectors that require top-tier protection, including healthcare and financial services.

Advantages of Advanced Encryption Standard (AES)

AES stands out as one of the most trusted encryption methods available today for several reasons:

1. Robust Security: AES is considered one of the strongest encryption standards. Its resistance to various attacks, especially brute-force attacks, makes it an excellent choice for protecting sensitive information. Longer key lengths (such as AES-256) provide even higher levels of security.
2. Efficiency in Hardware and Software: AES is efficient to implement in both hardware and software. It is optimized for performance, allowing data to be encrypted quickly without sacrificing security, making it ideal for applications that need both high speed and strong protection.
3. Ability to Secure Large Amounts of Data: Unlike some older encryption standards, AES can encrypt large volumes of data with minimal performance impact. This makes it ideal for applications that handle high data throughput, such as cloud storage, streaming services, and large databases.
4. Adaptability Across Industries and Devices: AES encryption is versatile and has become a global standard. It is used across many industries—from finance and healthcare to government and technology—providing reliable security across a wide variety of devices and systems.

Key Features of AES Encryption

AES is known for its reliability and efficiency, which make it a preferred choice for securing sensitive data. Key features include:

1. Symmetric Key Encryption: AES uses a symmetric key algorithm, meaning the same key is used for both encryption and decryption. This simplifies the process and improves speed, which is particularly useful for securing large volumes of data.
2. Multiple Key Sizes: AES supports key sizes of 128, 192, and 256 bits. These options provide flexibility, allowing users to choose a key length based on the desired balance between performance and security.
3. Block Cipher Method: AES uses a block cipher approach, dividing data into fixed-size blocks (typically 128 bits) and encrypting each block separately. This structure improves security by ensuring each block is independently protected.
4. Substitution-Permutation Network: The AES algorithm performs multiple rounds of substitution and permutation, transforming plaintext into ciphertext in a complex way. This design thoroughly mixes the data and makes it highly resistant to unauthorized access.
5. Efficient Performance: AES is optimized for both hardware and software, providing fast encryption and decryption speeds. This efficiency allows AES to protect data without significantly affecting performance, which is crucial for real-time applications.
6. Resistance to Known Attacks: AES is designed to be robust against known cryptographic attacks, including brute-force, differential, and linear cryptanalysis. This strength makes it suitable for high-security environments.

Real-World Applications of AES Encryption

AES is widely used across many sectors to ensure data security and privacy. Common applications include:

1. Wireless Security (Wi-Fi): AES is used in Wi-Fi security protocols like WPA2 and WPA3 to encrypt data sent over wireless networks. This helps protect sensitive information—such as passwords and personal details—from unauthorized access.
2. Encrypted Browsing (HTTPS): Websites use AES within HTTPS to secure data transmitted between browsers and servers. This encryption protects user information, such as login credentials and payment data, from interception by attackers.
3. Mobile Applications: Many mobile apps, especially those involving financial transactions or personal information, use AES to secure data stored on devices and data in transit. This includes banking apps, social media platforms, and messaging apps, giving users confidence that their data is protected.
4. Cloud Storage: AES is essential for securing files stored in the cloud. Services like Google Drive, Dropbox, and others use AES to help ensure that uploaded files remain confidential and protected against unauthorized access.
5. File and Disk Encryption: Operating systems like Windows and macOS offer AES-based encryption tools (such as BitLocker and FileVault) for securing entire drives or individual files. This is especially useful for protecting personal or sensitive business data on laptops and other devices.
6. Government and Military Communications: AES is a trusted standard for secure communication in government agencies and military operations. Its high level of security and resistance to attack make it suitable for protecting classified and sensitive information.
7. Secure Messaging: Many encrypted messaging applications, such as Signal and WhatsApp, use AES as part of their end-to-end encryption, ensuring that only the sender and recipient can read the contents of their conversations.

These use cases highlight AES’s versatility and reliability in protecting data across different environments and explain why it remains a trusted encryption standard worldwide.

Safeguarding AES Encryption: Key Attacks and Prevention Methods

AES encryption is highly secure, but like any encryption standard, it can be targeted by certain types of attacks. Below are common AES-related attack methods and ways to reduce the risks:

1. Brute-Force Attacks: In a brute-force attack, an attacker tries every possible key until the correct one is found. Although this approach is extremely time-consuming and computationally expensive, it becomes more realistic with very weak or short keys.
2. Differential Cryptanalysis: This technique studies how small changes in plaintext affect the resulting ciphertext. By analyzing these differences, attackers attempt to infer information about the key. AES is designed to be resistant to differential cryptanalysis, but understanding this threat helps reinforce strong encryption practices.
3. Side-Channel Attacks: Side-channel attacks exploit indirect information—such as power usage, timing, or electromagnetic emissions—instead of attacking the algorithm itself. Attackers use this “side” information to deduce the encryption key. These attacks usually require physical access to the device performing the encryption and are therefore more specialized.

How to Prevent AES Encryption Attacks

1. Use Longer Key Lengths: Longer keys make brute-force attacks far more difficult. AES-256, for example, offers significantly stronger protection than AES-128, greatly increasing the time and resources an attacker would need.
2. Ensure Key Secrecy: Store encryption keys securely and limit access to authorized personnel only. Dedicated key management solutions can help maintain strict control over keys and prevent unauthorized use.
3. Implement Physical Security Measures: To defend against side-channel attacks, protect the physical environment where encryption devices operate. Restrict physical access to servers, hardware security modules, and other devices performing encryption.
4. Regularly Update and Patch Systems: Keep software and firmware that implement AES up to date. Vulnerabilities in outdated systems can be exploited, so applying security patches promptly helps close gaps that attackers might target.
5. Avoid Weak or Predictable Keys: Always use a reliable cryptographic random number generator for key creation. Avoid keys that are easy to guess, follow patterns, or are derived from simple, predictable input.

By following these best practices, you can help ensure that AES encryption remains secure against potential attacks and continues to provide strong, reliable data protection.

AES Encryption vs. Other Encryption Standards

AES is widely adopted, but it is not the only encryption standard in use. Below is a comparison of AES with other common standards, such as DES and RSA, highlighting differences in security, speed, and efficiency.

RSA vs. AES

• Encryption Type: RSA is an asymmetric encryption method, using a pair of keys (public and private) for encryption and decryption. AES is a symmetric encryption method, using the same key for both operations.
• Security and Key Length: RSA typically requires much longer keys (such as 2048 or 4096 bits) to offer security comparable to AES-128, AES-192, or AES-256. Because AES uses shorter keys while maintaining strong security, it is usually faster and less resource-intensive.
• Efficiency: AES is more efficient for encrypting large amounts of data, which is why it is commonly used for bulk data encryption. RSA is generally used for smaller pieces of data, such as encrypting keys or establishing secure connections in SSL/TLS handshakes.

AES vs. DES

• Key Length and Security: DES (Data Encryption Standard) uses a 56-bit key, which makes it vulnerable to brute-force attacks. AES, by contrast, supports 128-, 192-, and 256-bit keys, offering much stronger protection.
• Algorithm Structure: DES uses a 64-bit block size, while AES uses 128-bit blocks, which contributes to AES’s improved resistance to certain types of cryptographic attacks.
• Efficiency and Modern Usage: AES is far more secure and efficient than DES. DES is now considered obsolete due to its short key length and known weaknesses, and AES has effectively replaced it in modern systems.

AES-128, AES-192, and AES-256 Differences

• Key Length: The main difference between these AES variants is key size. AES-128 uses a 128-bit key, AES-192 uses a 192-bit key, and AES-256 uses a 256-bit key.
• Security: Security increases with key length. AES-256 provides the highest level of protection and is often used in scenarios that demand maximum data security. AES-128 still offers strong security and is often chosen for less sensitive applications or those requiring maximum speed.
• Performance: AES-128 is the fastest of the three, followed by AES-192 and then AES-256. This trade-off between speed and security allows organizations to choose the option that best fits their performance requirements and risk tolerance.

Summary

The Advanced Encryption Standard (AES) is the modern foundation of data security, providing fast, reliable, and highly secure protection for sensitive information. Standardized by NIST to replace the outdated DES algorithm, AES uses symmetric key encryption and operates as a block cipher with key sizes of 128, 192, or 256 bits, with AES-256 offering the highest level of security. Its substitution–permutation design, efficient performance in both hardware and software, and resistance to known attacks make it the preferred choice across industries and applications, including Wi‑Fi security, HTTPS, mobile apps, cloud storage, disk encryption, government communications, and secure messaging. While AES can be targeted by brute-force, differential, or side-channel attacks, risks can be minimized by using strong key lengths, enforcing strict key management, maintaining physical and system security, and avoiding weak or predictable keys. Compared with RSA and legacy DES, AES delivers superior speed, scalability, and security for bulk data encryption, which is why solutions like Splashtop rely on AES-256 to deliver secure, high‑performance remote access for both businesses and individual users.