That’s where hashing and encryption come in. They both help protect information from prying eyes, but they work in different ways and are used for different purposes.

What is encryption?

Data is everywhere—and so are the risks of losing it. Whether you’re sending a message, logging into an account, or backing up your files, you want that data to stay private and secure.

That’s where hashing and encryption come in. They both help protect information from prying eyes, but they work in different ways and are used for different purposes.

How encryption works

At its core, encryption transforms your readable data (plaintext) into ciphertext, which looks like random gibberish. You need a key to reverse the process and make it readable again.

Only someone with the right key can unscramble it and turn it back into the original message.

There are two main types of encryption: symmetric and asymmetric.

Symmetric encryption uses the same key to lock and unlock the data. It’s fast and works well for encrypting files or entire hard drives. The tricky part is sharing that key safely. If someone else gets it, they can unlock your data too.

Asymmetric encryption solves that problem by using two keys: a public key and a private key. You can share the public key with anyone, and they use it to encrypt the data. Only your private key can decrypt it. This is how secure website logins and encrypted emails typically work.

Imagine a locked mailbox. Anyone can drop a message in using the public key (the mailbox slot), but only the owner with the private key (the mailbox key) can open it.

In most modern systems, both types are used together. Asymmetric encryption safely shares a secret key, and symmetric encryption handles the actual data. This way, you get both speed and security.

Common encryption algorithms (AES, RSA, DES, ECC…)

Some encryption methods have become standard over the years. Here’s a quick look at the most widely used ones:

AES (Advanced Encryption Standard)

AES is everywhere, from messaging apps to file encryption. It’s a symmetric algorithm known for being both fast and secure. It replaced older standards like DES and is trusted by governments, banks, and security-focused services.

RSA (Rivest–Shamir–Adleman)

RSA is a staple of asymmetric encryption. It’s slower than AES but ideal for encrypting small pieces of data, like keys or digital signatures. It’s widely used in SSL/TLS certificates and secure emails.

ECC (Elliptic Curve Cryptography)

ECC offers strong encryption with smaller key sizes. That makes it great for mobile apps, IoT devices, and cryptocurrencies, where speed, efficiency, and limited resources matter.

DES (Data Encryption Standard)

Once a go-to algorithm, DES is now outdated and vulnerable to attacks. It’s rarely used today, but it’s part of encryption’s history and a reminder of how fast security standards evolve.

Pros and cons of encryption

Encryption is powerful, but it’s not perfect. Here’s what it does well and where it falls short.

Pros

• Keeps sensitive data private, even if it’s stolen
• Protects data in transit and at rest
• Essential for secure communication, storage, and authentication
• Backed by decades of research and real-world use

Cons

• If your key is compromised, so is your data
• Managing keys at scale can be difficult and risky
• Slower than hashing, especially with asymmetric algorithms
• Doesn’t prove whether the data has been altered

What is hashing?

Hashing turns data into a fixed-length string of characters. This could be a file, password, or message. That string is called a hash.

Think of it like putting something into a blender. You can toss in a banana, peanut butter, and ice, and you’ll always get the same smoothie if you use the same ingredients. But once it’s blended, you can’t take it apart and get the original ingredients back.

That’s how hashing works. It’s a one-way process. The same input always gives you the same output, but there’s no practical way to reverse it and figure out what went in.

That’s why hashing is used for things like storing passwords or checking if a file has been tampered with. It doesn’t hide the data; instead, it helps prove that it hasn’t changed.

How hashing works

When you hash something, you run it through a special algorithm that creates a unique digital fingerprint. This fingerprint always has the same length, no matter how long or short the original data is.

Here’s what makes a good hashing function:

• Deterministic: The same input always produces the same hash
• Fast: It should generate the hash quickly
• One-way: You can’t reverse it to get the original input
• Collision-resistant: Two different inputs shouldn’t create the same hash

When you set a password, the system hashes it and stores that hash instead of the password itself. When you log in, your input is hashed again. If the new hash matches the one on file, you’re in. The actual password is never saved.

Even a tiny change to the input completely changes the hash. It’s like when you buy a drink: if the seal is broken, even slightly, you know something’s wrong. Hashes work in the same way. They’re used to confirm that nothing’s been altered, whether it’s a password or a downloaded file.

Common hashing algorithms (SHA-256, MD5, bcrypt…)

There are many hashing algorithms out there. Some are modern and secure; others are outdated and easy to break.

SHA-256 (Secure Hash Algorithm 256-bit)

SHA-256 is part of the SHA-2 family and one of the most widely used secure hash algorithms today. It’s used in everything from Bitcoin to SSL certificates. It produces a 256-bit hash that’s very hard to crack.

MD5 (Message Digest 5)

MD5 was once popular but is now considered broken. It’s fast but vulnerable to collisions, meaning two different inputs can produce the same hash, making it unsafe for security use.

bcrypt

bcrypt is designed specifically for hashing passwords. It includes a built-in delay (called a work factor) that makes it slower on purpose. This helps protect against brute-force attacks. It’s still a solid choice for password storage today.

Other common algorithms include SHA-1 (no longer considered secure) and Argon2, a newer password hashing algorithm designed to be secure and resistant to hardware-based attacks.

Pros and cons of hashing

Hashing has its strengths, but it also has limitations. Let’s explore the pros and cons.

Pros

• Ideal for storing passwords and verifying data integrity
• Fast and efficient
• One-way design protects original data from exposure
• Doesn’t require key management like encryption does

Cons

• Not reversible—once data is hashed, it can’t be recovered
• Vulnerable to brute-force or dictionary attacks without extra protection
• Some older algorithms (like MD5 or SHA-1) are easy to crack
• Not suitable for encrypting or transmitting sensitive data

Hashing vs encryption: A detailed comparison

Hashing and encryption both protect data, but they do it in very different ways. To understand which one to use (and when), it helps to compare them side by side.

Security differences

Encryption is all about privacy. It locks your data from unauthorized access with a secret key, keeping it confidential.

Hashing focuses on integrity. It doesn’t hide data; instead, it proves that it hasn’t been changed. The hash will be completely different if even a single bit is altered.

Although both methods can be secure, they’re still vulnerable to threats. Encryption can be broken if the key is stolen, weak, or mismanaged. Hashing can be attacked with brute-force attempts or precomputed lists (like rainbow tables), especially if no extra protection like salting is used.

In practice, encryption is stronger for keeping information private. Hashing is better for verifying data.

Speed and performance

Hashing is generally faster than encryption. It doesn’t have to manage keys or handle two-way communication. That makes it lightweight and ideal for quick tasks like checking passwords or verifying files.

Encryption is more resource-intensive, especially asymmetric encryption. Encrypting and decrypting data takes time, and handling keys adds overhead. This matters when you’re securing large files or working with limited hardware (like mobile or IoT devices).

• Hashing: Fast, simple, low CPU usage
• Encryption: Slower, especially with public/private keys, but more flexible

Reversibility: Can you retrieve the original data?

This is the biggest difference.

Encryption is reversible. You encrypt data so you can decrypt it later and retrieve the original information. It’s meant to temporarily protect something and then make it readable when needed.

Hashing isn’t reversible. Once data is hashed, there’s no going back. That’s the point. It’s a one-way function designed to verify, not to hide and later recover.

Encryption can be used to retrieve the original data. Hashing is used to confirm that data hasn’t changed or to securely store sensitive values, such as passwords.

Use cases: When to use hashing vs when to use encryption

Each method is designed for specific tasks. Using the wrong one can lead to serious security issues.

Use hashing when you want to:

• Store passwords securely
• Verify that files or messages haven’t been tampered with
• Check data integrity during downloads or backups
• Create digital fingerprints or components of digital signatures

Use encryption when you want to:

• Protect files, emails, or messages from being read
• Secure data during transmission (like HTTPS or VPN traffic)
• Store sensitive documents or databases safely
• Enable secure authentication or identity verification

Sometimes, using both together is the most secure approach. For example, you might encrypt a message to protect it and hash it to confirm that it hasn’t been altered.

Real-world applications and examples

Hashing and encryption are essential in today’s digital world. From logging into accounts to storing sensitive files, these technologies work behind the scenes to keep your data safe.

How hashing is used in password security

When you create a password for an online account, that password is almost never stored directly. Instead, the system hashes your password.

Here’s how it works:

• You create a password.
• The system runs it through a hashing algorithm and stores the hash.
• When you log in, your input is hashed again and compared to the stored version.

If the two hashes match, you’re granted access. The actual password is never saved, which helps keep it safe even if the database is exposed.

To make things even more secure, systems add a salt before hashing, which is a random string of data. This prevents attackers from using precomputed hash databases (rainbow tables) to crack passwords quickly.

Some systems use bcrypt or Argon2 for this. These are slow by design, making brute-force attacks much harder.

In short:

• Hashing protects passwords by making them unreadable and irreversible.
• Salting and secure algorithms reduce the risk of cracking.
• Even if hackers steal the database, the real passwords remain hidden.

How encryption is used for data protection

Encryption is everywhere—on your phone, in your browser, in your email, and in your cloud storage.

Here are just a few places where encryption is critical:

• Messaging apps: End-to-end encryption (like in Signal or WhatsApp) ensures that only the sender and receiver can read messages.
• HTTPS websites: Encrypt data in transit so attackers can’t intercept or read it.
• VPNs: Encrypt internet traffic to protect your activity from ISPs, hackers, or surveillance.
• Cloud services: Encrypt files at rest so data stays secure even if servers are compromised.
• Disk encryption: Tools like BitLocker or FileVault encrypt everything on your device in case it’s lost or stolen.

Encryption protects both privacy and control. You decide who can access your data, and you hold the keys.

In short:

• Encryption keeps files, messages, and connections private.
• It’s used for both storage (data at rest) and communication (data in transit).
• Without the right key, encrypted data is unreadable.

Hybrid approaches: Combining hashing and encryption

Hashing and encryption often work best when used together. They handle different parts of the security puzzle, so combining them covers more ground.

Here are some everyday examples where both are used side by side:

• Password storage: When you sign up for an account, your password gets hashed so no one can read it, not even the service itself. But when you type it in later, it’s sent over an encrypted connection (like HTTPS). That way, your password stays protected both in transit and at rest.
• Digital signatures: Say you’re downloading software from a trusted website. The developer creates a hash of the file and encrypts that hash with their private key. When you download it, your device uses their public key to verify the hash. If it matches, you know the file is legitimate and hasn’t been tampered with.
• Secure file transfers: Let’s say you’re sending a contract over email. You might encrypt the file so only the recipient can open it. But before sending, you also hash it. Later, the recipient can compare the hash you sent with the hash of the received file to make sure nothing changed along the way, even a single character.
• Login systems: When you log into an app, your password is hashed and checked against the stored version. At the same time, the login process itself happens over an encrypted connection. Once you’re in, the system might generate an encrypted token to keep your session secure.

Choosing the right method for your needs

The right choice depends on what you’re trying to protect and how you plan to use it.

Use hashing if you:

• Don’t need to recover the original data
• Want to securely store passwords
• Need to verify that data hasn’t changed (like file checks or digital signatures)
• Are working with systems that require fast, one-way data comparison

Use encryption if you:

• Need to keep information private and retrievable
• Are sending or storing sensitive data (like messages, emails, or documents)
• Need to control who can access the data
• Are working with user authentication, secure communications, or cloud storage

Sometimes, you may want to combine hashing and encryption. Use both if you:

• Want strong end-to-end security
• Are building login systems, secure messaging apps, or financial platforms
• Need to protect data from both tampering and unauthorized access

If you’re unsure, think of it like this: hashing locks the data in one direction, but encryption locks and unlocks it (with the right key). In many modern systems, both are essential. Using them together adds an extra layer of protection that’s hard to beat.

Summary

FAQ: Hashing vs encryption: Key differences

Can hashed data be decrypted?

No. Hashing is a one-way process, so you can’t reverse it to get the original data back. Once something is hashed, there’s no built-in method to decrypt or recover the original input. That’s what makes hashing useful for things like password storage and data verification, as it protects the original data by making it impossible to read directly. While attackers can try to guess the input using brute force or lookup tables, proper hashing techniques like salting make that extremely difficult.

Is encryption more secure than hashing?

Not exactly—it depends on the purpose. Encryption is better when you must protect sensitive data and access it later. Hashing is best for verifying data without revealing it. Encryption keeps data private by scrambling it, while hashing ensures data hasn’t been altered. Both are secure in their own way, but they serve different goals. Combining them often provides stronger overall protection, especially in systems that handle login credentials, messaging, or file transfers.

Which method is best for storing passwords?

Hashing is the best method for storing passwords, not encryption. Because hashing is one-way, it keeps passwords safer even if someone gets access to the database. You should also use salting and strong hashing algorithms like bcrypt or Argon2. These make it harder for attackers to use precomputed lists or brute-force tactics. Encryption is reversible, so every password becomes exposed if the key is ever compromised. Hashing with salting provides better long-term protection for stored credentials.

What is salting and how does it improve hashing?

Salting adds a random string to a password before it’s hashed. This ensures that even if two people have the same password, their hashes look different. Salting stops attackers from using precomputed databases (rainbow tables) to match common password hashes quickly. Each person gets a unique salt, making mass cracking much harder. Modern hashing methods like bcrypt include salting by default. It’s a simple but powerful way to make password storage more secure.

What is the difference between hashing and encryption?

Hashing is a one-way process used to verify data or store it securely without retrieving the original input. Encryption is a two-way process that scrambles data to keep it private, but it can be reversed with a key. Hashing is used for things like password protection and file verification. Encryption is used to protect sensitive data during transmission or storage. The key difference: encryption is reversible, hashing isn’t.

Is SHA-256 encryption or hashing?

SHA-256 is a hashing algorithm, not an encryption algorithm. It takes input data and produces a fixed-length 256-bit hash. You can’t reverse it or decrypt it, so it’s useful for verifying integrity and checking data. SHA-256 is part of the SHA-2 family and is widely used in applications like blockchain, SSL certificates, and file validation. It’s fast, secure, and collision-resistant but shouldn’t be used alone for password storage. Methods like bcrypt or Argon2 are better suited for that.

Is hash the same as encrypted?

No. Hashing and encryption are two different processes. Hashing creates a fixed, one-way fingerprint of data that can’t be reversed. Encryption scrambles data so it’s unreadable without a key, but it can be decrypted back to its original form. You’d hash something when you want to check if it has changed or to protect it without needing to access it again. You’d encrypt something when you want to keep it private and still be able to read it later.

When should I use both hashing and encryption together?

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.

Understanding the ChaCha20 algorithm

To understand the ChaCha20 algorithm, it’s helpful to break it down into its core elements: its origin, the process it uses to produce encrypted data, and the role of its key, nonce, and counter. Each of these parts works together to provide speed, efficiency, and security, making ChaCha20 a strong option in many modern encryption protocols.

Who developed ChaCha20 and why?

ChaCha was developed in 2008 by Daniel J. Bernstein, an American-German mathematician, computer scientist, and cryptographer. It’s based on his earlier design, Salsa20.

One of the main reasons for creating ChaCha20 was to provide a strong alternative to widely used ciphers like Advanced Encryption Standard (AES). While AES is very secure, it runs fastest on devices that support hardware acceleration: special CPU instructions, like Intel’s Advanced Encryption Standard New Instructions (AES-NI), which speed up its operations. Many older, mobile, or low-power devices don’t have this hardware support, making AES slower and more battery-hungry when implemented purely in software.

ChaCha20 was designed to avoid this problem. It uses only simple operations that run quickly on virtually any processor. This lightweight design makes it especially well-suited for smartphones, embedded systems, and other constrained environments. Today, ChaCha20 is recommended in modern protocols such as Transport Layer Security (TLS) 1.3 as a reliable option alongside AES.

How ChaCha20 works

Let’s say you want to encrypt this message using ChaCha20: “ExpressVPN protects my online privacy and helps keep my data safe.” Here’s how this is done, step by step.

1. Turn the message into bytes.

Computers work with bytes, which are 8-bit units that can store a number from 0 to 255. Text like our sentence is stored by mapping each character (“E,” “x,” space, “.”, etc.) to 1 byte. Our sentence is 66 bytes long, so it will take a little more than one 64-byte chunk (block) to encrypt.

2. Next, you need a secret key.

ChaCha20 is a symmetric cipher, which means the same secret is used to encrypt and decrypt. That secret is a 256-bit key (32 bytes). You can think of it as a long, random password that only the sender and receiver know. Why 256 bits? It’s large enough that guessing it by trial and error is effectively impossible.

3. You also need a nonce (number used once).

A nonce is a public, unique number chosen for each message you encrypt with a given key.

In the Internet Engineering Task Force (IETF) version of ChaCha20, the nonce is 96 bits (12 bytes). It doesn’t have to be secret, but it must never repeat with the same key. Reusing a key–nonce pair would reveal your message.

4. ChaCha20 makes a keystream.

ChaCha20 belongs to the “stream cipher” family. Instead of directly scrambling your message, it first produces a stream of pseudo-random bytes called a keystream. You then combine that keystream with your message bytes using a simple operation called exclusive OR (XOR) .

How does ChaCha20 make the keystream?

Build an internal state

ChaCha20 keeps a small working area called the state, arranged as a 4×4 grid of numbers. Each number in the grid is a word, which here means a 32-bit (4-byte) unsigned integer like, for example, 00000000 00000000 00000111 01001001.

The 16 words in the grid are filled with:

• 4 fixed constants (they just identify the algorithm),
• 8 words from the 256-bit key (since 8 × 4 bytes = 32 bytes),
• 1 block counter (explained next),
• 3 words from the nonce (3 × 4 bytes = 12 bytes).

The block counter

The keystream is produced in blocks of 64 bytes at a time.

To make each 64-byte block different, ChaCha20 uses a 32-bit counter inside the state that starts at 0 for the first block, 1 for the next block, and so on.

Mix the state (the ARX core)

ChaCha20 repeatedly mixes the 16 words from the grid using only three operations: addition (modulo 2³²), rotation (bitwise rotation of 32-bit words), and XOR (which compares two bits and outputs 1 if they’re different and 0 if they’re the same).

This mixing, based on Addition, Rotation, and XOR (ARX) operations, is done in rounds (ChaCha20 does 20 rounds). The key point is that these simple, fast operations thoroughly scramble the state in a way that’s hard to reverse without the key.

Produce 64 bytes of keystream

After the mixing, ChaCha20 adds the original state to the mixed state (word by word) and then outputs the result as 64 keystream bytes. That’s one keystream block.

5. Make as many keystream blocks as needed

Your message can be any length. ChaCha20 simply uses counter = 0 to make the first 64 bytes of keystream, counter = 1 for the next 64 bytes, counter = 2 for the next 64 bytes, and so on. Because the counter changes, each keystream block is unique (even with the same key and nonce).

6. Line up keystream with your message

Our example message is 67 bytes, so block 0 covers message bytes 0–63 (64 bytes), and block 1 covers message bytes 64–66 (the last 3 bytes). We only use the first 3 bytes from the second keystream block and ignore the rest.

7. Combine message with keystream using XOR

XOR is a per-byte operation with a neat property: doing the same XOR twice gets you back where you started:

Encryption (per byte): plaintext XOR keystream = ciphertext

Decryption (per byte, same keystream): ciphertext XOR keystream = plaintext

Comparing ChaCha20 with other ciphers

While ChaCha20 is widely used today, it’s not the only encryption algorithm in play. Other ciphers, like AES and Rivest–Shamir–Adleman (RSA), are also common, but they work in different ways and are suited for different tasks. Comparing them helps show where ChaCha20 fits in and why certain protocols choose it over the alternatives.

ChaCha20 vs. AES

ChaCha20 and AES are both symmetric key encryption algorithms, meaning the same key is used for both encryption and decryption. To better understand various cryptographic techniques, including the differences between encryption and hashing, you can check out this explanation of hashing vs. encryption.

The main difference between ChaCha20 and AES lies in how they process data. AES is a block cipher, encrypting data in fixed-size blocks, while ChaCha20 is a stream cipher, generating a continuous keystream that’s combined with the data.

AES often benefits from hardware acceleration on modern processors, which makes it extremely fast in those environments. ChaCha20, on the other hand, is designed to perform consistently well even without specialized hardware support, making it a strong choice for mobile devices and low-power systems. That’s why ExpressVPN uses both AES-256 and ChaCha20 for its Lightway protocol, automatically switching to the one best suited for your device (you can also choose one or the other manually).

Another practical difference is in implementation. AES can be more complex to code securely, as it may be vulnerable to timing attacks if not implemented carefully. ChaCha20 uses simple ARX operations that naturally run in constant time, helping reduce this risk.

Both ciphers are considered secure when properly implemented, and modern protocols like TLS 1.3 include support for each. The choice between them depends on the device’s hardware and performance requirements rather than on security concerns.

ChaCha20 vs. RSA

ChaCha20 and RSA aren’t direct competitors: they perform different functions in secure communication.

RSA is an asymmetric encryption algorithm, meaning it uses a key pair: one public and one private. It’s typically used at the start of a secure connection to exchange encryption keys or verify identities. In TLS, the symmetric-key algorithm is often AES, with the key exchange secured by RSA.

Because RSA involves more complex mathematics and operates on larger key sizes, it’s slower and less efficient for continuous data encryption.

ChaCha20, on the other hand, is a symmetric stream cipher. It uses a single shared key for both encryption and decryption, making it faster and better suited for ongoing data transfer.

In practice, many secure protocols combine both approaches: RSA (or another asymmetric algorithm) for the initial handshake and ChaCha20 or another symmetric cipher for the rest of the session.

Advantages of ChaCha20

ChaCha20 is popular not only because it’s secure but also because it works well in real‑world situations. It’s fast on all kinds of devices, even phones and gadgets with less power. Its design is straightforward, which helps avoid common mistakes that can weaken encryption.

Speed and performance on mobile and low-power devices

ChaCha20 is designed to work efficiently on all kinds of hardware, not just high‑end processors. On devices without AES hardware acceleration, such as many smartphones, tablets, or IoT devices, it can run noticeably faster.

Simplicity and resistance to timing attacks

ChaCha20 is built around simple ARX operations. These run in constant time, meaning the execution speed doesn’t change based on the data being processed: all operations take the exact same time.

This design makes it easier to implement securely and helps protect against timing attacks, which try to extract information by measuring how long encryption steps take.

What are the known limitations of ChaCha20?

ChaCha20 has been studied for years, and no real‑world breaks of the full 20‑round version have been published. Overall, it’s the most thoroughly tested alternative to AES there is today. However, it has some clear limits that developers should keep in mind. Using it outside these boundaries can weaken its protection.

• Nonce reuse is a serious risk: Using the same nonce with the same key instantly breaks confidentiality. Each nonce–key pair must be unique.
• No built-in authentication: ChaCha20 only encrypts data. To check that data hasn’t been altered, it should be used with Poly1305.
• Limit on encrypted data per key/nonce: ChaCha20 can handle up to 2³² blocks of 64 bytes (about 256 GB) with the same key and nonce. Passing this limit would result in keystream reuse and completely undermine the security of the encryption.

ChaCha20-Poly1305 explained

ChaCha20‑Poly1305 is a pairing of two cryptographic components that work together to protect data:

• ChaCha20 encrypts information with a shared secret key, turning readable text into something that looks like random data to anyone without the key. However, it doesn’t detect tampering.
• Poly1305 produces a message authentication code (MAC) that lets the receiver confirm the data hasn’t been altered and that it came from the right source.

Together, they form what’s known as Authenticated Encryption with Additional Data (AEAD). This means the encryption process not only hides the contents of the message but also verifies its integrity.

Poly1305 isn’t the only option, but it’s the most common choice when ChaCha20 is used in modern protocols. That’s because ChaCha20‑Poly1305 has been standardized by the IETF (RFC 8439) and is widely supported in TLS, SSH, WireGuard, and other protocols, so it’s the de facto standard.

ChaCha20 in 2025: Where it’s used in modern systems

ChaCha20 has become a standard choice in many security‑focused applications. In internet security, it’s used in TLS connections, often together with Poly1305, to protect HTTPS traffic, especially on devices that don’t have hardware support for AES. Major browsers like Chrome and Firefox, and web servers such as nginx and Apache, support this cipher suite.

It’s also widely used in virtual private networks (VPNs). The WireGuard VPN protocol, for example, sets ChaCha20‑Poly1305 as its default to secure data while keeping performance high on mobile and embedded devices. Support is also built into major operating systems, including Linux, Android, iOS, and Windows.

Summary

FAQ: Common questions about ChaCha20

Does Google use ChaCha20?

Yes. Google adopted ChaCha20 with Poly1305 in 2014 as part of its Transport Layer Security (TLS) / Secure Sockets Layer (SSL) protocols. The goal was to improve performance and security for mobile devices and servers that lack Advanced Encryption Standard (AES) hardware acceleration, making secure connections faster and more efficient in those environments.

Is ChaCha20 quantum-resistant?

Yes. Symmetric ciphers, like ChaCha20, are generally regarded as quantum-safe, provided they use sufficiently long keys (e.g., 256 bits).

Can ChaCha20 be used for file encryption?

Yes. ChaCha20 can be used in file encryption tools to protect sensitive data stored on devices. Its speed and efficiency make it suitable for both large files and devices with limited processing power.

Can ChaCha20 be cracked?