What is AES encryption?

AES (Advanced Encryption Standard) is a *symmetric block cipher* used by governments and organizations worldwide to secure sensitive data. 'Symmetric' means it uses the *same secret key* to both encrypt and decrypt data. 'Block cipher' means it encrypts data in fixed 128-bit blocks.

Is AES secure? Can it be broken?

Yes, AES is considered highly secure and is the 'gold standard' for data encryption. The U.S. government uses AES-256 to protect 'TOP SECRET' information. As of today, there is no known practical attack that can break AES-256 encryption. Its security relies entirely on keeping the *secret key* or *password* secure.

What's the difference between AES-128, AES-192, and AES-256?

The numbers refer to the *key size* in bits. AES-128 uses a 128-bit key, AES-192 uses a 192-bit key, and AES-256 uses a 256-bit key. A longer key means exponentially more possible combinations, making it stronger against brute-force attacks. AES-256 is the most secure standard.

What is the difference between AES and RSA?

AES is *symmetric* (uses one shared key). It is very fast and used to encrypt large amounts of data (like a file or message). RSA is *asymmetric* (uses a *public key* to encrypt and a *private key* to decrypt). It is much slower and is typically used to securely *exchange* the AES secret key, or for digital signatures.

AES Encryption / Decryption Tool

Secure client-side encryption using the WebCrypto API (AES-256).

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Your Security Matters: Client-Side WebCrypto API

All operations happen in your browser.
This tool uses the browser's native **WebCrypto API**, the modern standard for secure client-side cryptography.
Your password, key, or data is never stored or sent to our servers.

What is AES? The Gold Standard of Encryption

AES, or **Advanced Encryption Standard**, is the global "gold standard" for **symmetric encryption**. It's a block cipher adopted by the U.S. government to protect classified information.

Key Concepts:

Symmetric Encryption: This is the biggest difference from Hashing or Encoding. Symmetric means the **same secret key** (or password) is used to *both* encrypt and decrypt the data. You *must* share this key securely with the recipient.
Block Cipher: AES operates on fixed-size 128-bit (16-byte) blocks of data.
Key Sizes (AES-128 vs. AES-256):** The numbers refer to the key length. **AES-256** uses a 256-bit key and is the standard for "TOP SECRET" data, offering the highest level of security.

AES vs. RSA:** AES is *symmetric* (one key) and very fast, perfect for encrypting large messages or files. RSA is *asymmetric* (public/private key pair), is much slower, and is used to securely *exchange* the AES secret key.

Modes (GCM vs. CBC):**

**AES-GCM:** The modern, recommended mode. It's fast and provides **Authenticated Encryption (AEAD)**, which means it ensures both *confidentiality* (secrecy) and *authenticity* (proof the data wasn't tampered with).

**AES-CBC:** A classic, reliable mode. It requires an "Initialization Vector" (IV) to ensure security. It only provides confidentiality.

This tool uses your password to derive a secure key (using PBKDF2) and then encrypts/decrypts your data *entirely in your browser* using the native **WebCrypto API**. Your data never leaves your computer.

AES Encryption Examples

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AES Best Practices & Key Concepts

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Encryption is NOT Hashing

This is the most common confusion. **Hashing (SHA-256)** is a one-way function to *verify* data (passwords, files). **Encryption (AES)** is a two-way function to *protect* data (messages, secrets). You can decrypt AES with the key. You can *never* "decrypt" a SHA-256 hash.

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Your Key is Your Security

The AES-256 algorithm itself is unbreakable by any known force. The *only* weak point is your **secret key/password**. If you use a weak password ("12345"), your "unbreakable" encryption can be broken in seconds. Use a long, random, and complex password.

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Always Use Authenticated Encryption (GCM)

Older modes like CBC only protect *confidentiality*. An attacker could still "flip bits" in the ciphertext and corrupt the decrypted message. **AES-GCM** is the modern standard because it's an AEAD (Authenticated Encryption) mode. It provides both confidentiality *and* authenticity, meaning you are 100% sure the data was not tampered with.

Frequently Asked Questions (AES)

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