Over the years, I’ve built and maintained multiple online cryptography tools — AES encryption, ChaCha20 encryption, RSA encryption, and several hashing utilities.
On the surface, all these tools look similar. You provide some input, click a button, and get encrypted or hashed output.
But while working on these tools and reading user comments, I noticed a recurring pattern:
many users are confused about why different encryption algorithms require different inputs.
Why does ChaCha20 need a nonce?
Why does AES talk about modes and padding?
Aren’t they all just “encryption” in the end?
This post is my attempt to answer those questions in a practical, beginner-friendly way.
Encryption Looks Simple — Until You Build It
From a high level, encryption tools feel identical. You enter plaintext, provide a secret key, and receive ciphertext.
But once you implement them, the differences become obvious:
- Some algorithms ask for an IV
- Some require a nonce
- Some expose modes
- Others hide complexity to prevent misuse
These differences come directly from how each algorithm is designed.
Why AES Has So Many Options
AES (Advanced Encryption Standard) is a block cipher.
It encrypts data in fixed-size blocks (128 bits at a time).
Because of this, AES must be used with a mode of operation such as CBC, CTR, or GCM.
That’s why AES tools often expose:
- Encryption mode
- Initialization Vector (IV)
- Padding scheme
AES is also extremely fast on modern CPUs thanks to hardware acceleration (AES-NI), which is why it dominates server-side environments.
Why ChaCha20 Needs a Nonce
ChaCha20 works very differently.
It’s a stream cipher, meaning it generates a pseudorandom keystream and XORs it with plaintext.
Instead of modes and padding, ChaCha20 relies on:
- A 256-bit secret key
- A nonce (number used once)
- An internal counter
Users often ask why the nonce matters so much.
The reason is simple: stream ciphers must never reuse the same keystream.
If you want to experiment with nonce reuse and see how output changes, a
ChaCha20 encryption tool
can make this behavior very clear.
AES vs ChaCha20 (Quick Comparison)
| Aspect | AES | ChaCha20 |
|---|---|---|
| Cipher Type | Block cipher | Stream cipher |
| Random Input | IV (mode-dependent) | Nonce |
| Modes Required | Yes | No |
| Padding | Often required | Not required |
| Hardware Acceleration | Yes | No |
| Mobile Performance | Good | Excellent |
Final Thoughts
AES and ChaCha20 both solve the same problem — turning readable data into unreadable data — but they approach it very differently.
- AES shines on servers and compliance-heavy systems
- ChaCha20 excels on mobile, browsers, and constrained environments
If you understand why certain fields exist in your encryption tools, choosing the right algorithm becomes much easier.
👉 Read the full in-depth guide with real-world mistakes and FAQs:
https://www.devglan.com/crypto/aes-vs-chacha20
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