AES Decrypt
Decrypt AES encrypted text
Frequently Asked Questions
How does AES decryption work?
AES decryption reverses the encryption process using the same key. It applies inverse operations: InvShiftRows, InvSubBytes, InvMixColumns, and AddRoundKey in reverse order. AES-128 uses 10 rounds, AES-256 uses 14 rounds. The tool decrypts ciphertext with your key.
What do I need to decrypt an AES-encrypted message?
You need: the ciphertext, the encryption key (128, 192, or 256 bits), the mode (CBC, GCM, ECB), and the initialization vector (IV) for CBC/GCM modes. Without the correct key and parameters, decryption is impossible.
What is the difference between AES-CBC and AES-GCM decryption?
CBC (Cipher Block Chaining) decrypts blocks sequentially using the IV. GCM (Galois/Counter Mode) decrypts in parallel and also verifies data integrity via an authentication tag. GCM is preferred for its built-in authentication.
Why does my AES decryption produce garbled output?
Common causes: wrong key, wrong mode (CBC vs GCM vs ECB), wrong IV, wrong padding scheme (PKCS7 vs zero padding), encoding mismatch (Base64 vs hex), or corrupted ciphertext. Verify all parameters match the encryption settings exactly.
Can AES encryption be broken without the key?
AES-256 is considered unbreakable with current technology. A brute-force attack would require 2^256 attempts, which would take billions of years with all computers on Earth combined. AES is approved for US government top-secret data.