How to AES Decrypt Text
AES Decryption
When to Decrypt AES Ciphertext
Decrypt AES-GCM payloads from config files, debug encrypted API responses, or verify round-trip encryption during development. Provide the same key and IV used during encryption, plus the base64 ciphertext.
Requirements for Success
Decryption requires the exact AES key, IV, and ciphertext produced during encryption. Paste ciphertext-only base64 with IV in Tool Settings, or paste combined base64(IV + ciphertext) with IV left blank. Mismatched values produce errors rather than partial output.
Developer Tips
- Test encrypt/decrypt round-trip on sample data before production integration
- Store keys in secret managers — not in source code or shared documents
- Clear decrypted plaintext from the page after inspection on shared machines
Frequently asked questions
Why does decryption fail with a valid-looking key?
Wrong key, wrong IV, corrupted ciphertext, or a different AES mode are common causes. Verify all values match the encryption step exactly.
Is decrypted output stored anywhere?
No. Decryption runs in your browser only. Clear sensitive plaintext after copying.
Why is there no padding option?
This tool uses AES-GCM, which encrypts plaintext of any length without PKCS7 padding. If you need AES-CBC with PKCS7, use a library that supports that mode — settings are not interchangeable.