AES Encryptor / Decryptor

AES (Advanced Encryption Standard) with 256-bit keys and GCM (Galois/Counter Mode) is the encryption algorithm used by governments, banks, and security-critical applications worldwide. AES-256 provides 256-bit symmetric key strength — computationally infeasible to brute-force. GCM mode adds authenticated encryption: it simultaneously encrypts your data and generates an authentication tag, so any tampering with the ciphertext is detected during decryption. This makes AES-256-GCM both confidential and tamper-proof.

Your password is never used directly as the AES key. Instead, it's run through PBKDF2 (Password-Based Key Derivation Function 2) with 100,000 iterations of HMAC-SHA256 and a random 16-byte salt. This slow derivation makes brute-force attacks against weak passwords much harder. The derived 256-bit key is only held in memory during the operation and never stored or transmitted.

The IV (or nonce) is a 12-byte random value that ensures the same plaintext encrypted with the same key produces a different ciphertext every time. Without a unique IV, identical plaintexts would produce identical ciphertexts, leaking information about your data patterns. This tool generates a new random IV for each encryption operation using the browser's cryptographically secure random number generator (crypto.getRandomValues).

The output is a base64-encoded token that embeds everything needed to decrypt: the salt (16 bytes), IV (12 bytes), GCM authentication tag (16 bytes), and the ciphertext. You only need the password and this single token to decrypt — no separate storage of salt or IV is needed. The base64 encoding makes the output safe to copy into text fields, URLs, and JSON.

This tool uses the browser's built-in Web Crypto API (crypto.subtle) — the same API used by password managers and security tools. Your data is processed entirely in your browser; nothing is sent to any server. The algorithm (AES-256-GCM with PBKDF2 key derivation) is cryptographically sound. However, security also depends on your password strength — use a long, random passphrase for sensitive data.

Yes. The format is standard: 16-byte salt + 12-byte IV + 16-byte GCM tag + ciphertext, all base64-encoded. Derive the key using PBKDF2 (SHA-256, 100,000 iterations, 256-bit output), then decrypt with AES-256-GCM. Examples exist in Node.js (crypto module), Python (cryptography library), and any language with a Web Crypto-compatible API.