AES (Advanced Encryption Standard) is a symmetric block cipher adopted worldwide to protect data. It encrypts 128‑bit blocks using keys of 128, 192, or 256 bits. This tool implements AES in several modes so you can securely encrypt text right in your browser.

CBC (Cipher Block Chaining) is the most widely used and secure mode for general purposes. ECB does not use an IV and reveals patterns – only use it for single-block data. CFB, OFB, and CTR are stream-like modes useful for specific streaming or error-tolerant needs. Always use a unique, random IV with modes that require it.

The key must be exactly 16, 24, or 32 bytes (characters) long. In “Text” mode each character is one byte (UTF‑8). In “Hex” mode the string length must be 32, 48, or 64 hex digits. The IV is always 16 bytes – 16 characters in Text mode, 32 hex digits in Hex mode. The tool warns you if the length is wrong.

Base64 is more compact (about 33% smaller) and commonly used in web applications. Hex (hexadecimal) is easier to read and debug. Both encode the same raw encrypted bytes. You can decrypt using the format you originally chose.

Absolutely – everything runs inside your browser. No data is ever sent to a server. Your keys, messages, and encrypted output stay on your device. We don't log, store, or see any of it.

Yes. Use the same AES variant (mode, key, IV, and padding – PKCS#7). Provide the raw encrypted bytes (Base64 or Hex decoded) and you’ll get back the original text. Common libraries like OpenSSL, CryptoJS, PyCryptodome, and Java's Cipher support these parameters.