AES Encryption / Decryption

AES (Advanced Encryption Standard) is a symmetric encryption algorithm widely used to secure data. It operates on 128-bit blocks and supports key sizes of 128, 192, and 256 bits. AES is the most widely adopted encryption standard worldwide.

CBC (Cipher Block Chaining) chains blocks together for better security. CFB (Cipher FeedBack) turns AES into a self-synchronizing stream cipher. CTR (Counter) uses a counter for parallelizable encryption. OFB (Output FeedBack) creates a keystream for stream encryption. ECB (Electronic Code Book) encrypts each block independently — least secure, not recommended for large data.

Padding adds extra bytes to align data to block boundaries. Pkcs7 is the most common and recommended padding. Iso97971 adds a byte before Pkcs7 padding. AnsiX923 fills with zeros and a length byte. Iso10126 uses random bytes with a length byte. ZeroPadding fills with zero bytes. NoPadding requires input to be exactly block-aligned.

Encryption output uses Base64 encoding by default, which is the most common and compact format. Key and IV inputs support auto-detection of Hex, Base64, or UTF-8 format — simply paste your key or IV and the tool will automatically recognize the format.

Use strong random keys (use the generate button). Prefer CBC or CTR mode over ECB. Use AES-256 for maximum security. Always use a unique IV for each encryption in CBC, CFB, CTR, and OFB modes. Never reuse the same key-IV combination.

No, all encryption and decryption is performed locally in your browser using the CryptoJS library. Your data, keys, and IVs never leave your device.

AES supports three key sizes: 128 bits (16 bytes), 192 bits (24 bytes), and 256 bits (32 bytes). AES-128 is sufficient for most uses, AES-192 provides extra security margin, and AES-256 offers the highest security level recommended for classified data.