AES Encryption & Decryption Online
AES-128 and AES-256 encryption and decryption tool with ECB and CBC modes. Enter your key and IV, encrypt or decrypt data instantly — 100% client-side.
Frequently Asked Questions about AES Encryption
How do I encrypt text with AES online?
Enter your plaintext, select AES-128 or AES-256, choose ECB or CBC mode, provide a key (and IV for CBC), then click Encrypt. The result is Base64-encoded ciphertext.
What is the difference between AES-128 and AES-256?
AES-128 uses a 128-bit (16-byte) key and AES-256 uses a 256-bit (32-byte) key. AES-256 provides stronger security but both are considered safe for most applications.
What is the difference between ECB and CBC mode?
ECB (Electronic Codebook) encrypts each block independently, which can reveal patterns. CBC (Cipher Block Chaining) uses an IV and chains blocks together, providing better security for most use cases.
Is this AES encryption tool secure?
Yes, all encryption and decryption happens 100% in your browser using the CryptoJS library. Your data and keys never leave your device and are not sent to any server.
What key and IV length should I use?
For AES-128, use a 16-character key. For AES-256, use a 32-character key. The IV (Initialization Vector) for CBC mode should always be 16 characters.
Can I decrypt data encrypted by another tool?
Yes, as long as the same algorithm, mode, key, and IV were used. The ciphertext should be Base64-encoded. This tool uses PKCS7 padding by default.
Is my data sent to any server?
No. This tool runs entirely in your browser. No data, keys, or results are ever transmitted over the network.