About the Text Decrypt
This is the receiving half of the pair. Someone hands you a Base64 or hex blob and a password; drop the blob in the left pane, put the password in the toolbar, and the plain text appears. The cipher, the salt and the initialisation vector are all read out of the header that travels inside the blob, so there is nothing else to configure and no algorithm to guess.
Both encodings are accepted. A run of hex digits with an even length is detected automatically, anything else is treated as Base64, and Base64 that lost its padding during a copy is repaired before decoding. Line breaks introduced by an email client are stripped. What cannot be repaired is a truncated blob, so if a message was cut short you will see a message saying the payload is too short to hold a salt and an initialisation vector.
A wrong password fails in one of two ways. Under AES-GCM the authentication tag rejects the attempt immediately. Under AES-CBC the padding usually breaks, and if it happens to survive, the recovered bytes are checked as strict UTF-8 and rejected when they are not readable text. Either way you get a clear message rather than a page of mojibake. Produce ciphertext for this page with Encrypt Decrypt. If the string you hold is only Base64 and not encrypted at all, Base64 Decode is the tool you actually want.
How to use
- Paste the ciphertext into the left pane, line breaks and all.
- Type the password that was used to encrypt it into the Password box.
- Read the recovered text on the right, or the error message explaining what went wrong.
- Copy or download the plain text once it looks right.
Common questions
- It says decryption failed. What now?
- Check the password character by character, then confirm the whole ciphertext was copied including any trailing equals signs.
- Can I decrypt something encrypted elsewhere?
- Only if it came from the Encrypt Decrypt page on this site. Other tools use different key derivation, so their output has no matching header here.
- Do I need to say whether it was GCM or CBC?
- No. The cipher is recorded in the header inside the ciphertext and read back automatically.
- Is the password sent anywhere?
- No. Key derivation and decryption both run in the browser through WebCrypto, so the password stays on your machine.