What is AES encryption and how does it work?

AES (Advanced Encryption Standard) is a symmetric block cipher adopted by NIST in 2001. It encrypts data in 128-bit blocks using a 128, 192, or 256-bit key. AES-256 provides 2^256 possible keys — effectively unbreakable with current computing power. This tool uses PBKDF2 to derive a strong AES key from your passphrase.

What is the difference between AES-GCM, CBC, and CTR modes?

GCM (Galois/Counter Mode) is authenticated encryption — it encrypts and produces an authentication tag to detect tampering. Recommended for most uses. CBC (Cipher Block Chaining) is the classic mode with PKCS7 padding — widely compatible but no auth tag. CTR (Counter Mode) is a stream cipher variant — fastest, no padding, but no authentication.

Why do I need to save IV and Salt? What happens if I lose them?

The IV (Initialization Vector) and Salt are required for decryption — without them it is mathematically impossible to decrypt the ciphertext, even with the correct password. They do not need to be secret, just stored. Always save them alongside your encrypted data.

Is this AES tool safe for encrypting real passwords or sensitive data?

This tool is safe for learning and moderate-security use cases. It uses the browser Web Crypto API (native, audited implementation) with strong PBKDF2 key derivation. For production security systems handling highly sensitive data, always use server-side implementations with professional security audits.

What is PBKDF2 and why 100,000 iterations?

PBKDF2 (Password-Based Key Derivation Function 2) converts your human-readable passphrase into a strong cryptographic key using a random salt and repeated SHA-256 hashing. 100,000 iterations makes brute-force attacks computationally expensive — an attacker trying millions of passwords would need enormous time and resources.

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AES Encrypt / Decrypt Online — AES-256, GCM, CBC, CTR

AES-128 · AES-192 · AES-256 · GCM · CBC · CTR — PBKDF2 key derivation · 100% browser-side

Key

Out

AES-GCM

Authenticated encryption — tamper-proof. Recommended.

✅ Recommended

AES-CBC

Classic block cipher mode. PKCS7 padding. No auth tag.

AES-CTR

Stream cipher mode — no padding, fast. No auth tag.

Plaintext to Encrypt

🔑 Password / Passphrase

PBKDF2 derives a 256-bit AES key — 100,000 SHA-256 iterations + random salt

IV — 96-bit IV (12 bytes)

⚠️ Save this for decryption!

Salt — 128-bit (16 bytes)

⚠️ Save this for decryption!

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Enter text + password to encrypt

AES-256-GCM recommended — authenticated + tamper-proof

Ctrl+Enter Encrypt Ctrl+L Clear Ctrl+S Download

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AES Encrypt/Decrypt by CalcNation — symmetric encryption using AES-128/192/256 with GCM, CBC, and CTR modes. Password-based key derivation via PBKDF2 (100,000 iterations). All operations run 100% in your browser — nothing is ever uploaded or stored.