Decrypt and verify ChaCha20-Poly1305 or XChaCha20-Poly1305 text or files online using a 256-bit key, nonce, AAD, tag, and PBKDF2, EvpKDF, HKDF, Scrypt, or Argon2 key derivation. Read more
ChaCha20-Poly1305 decryption online
Decrypt and verify ChaCha20-Poly1305 or XChaCha20-Poly1305 ciphertext. Keep Append Tag enabled when the final bytes of the input contain the authentication tag. Disable it when the tag is stored separately, then enter the detached Authentication Tag.
How to decrypt
Paste ciphertext or upload a file and select the input encoding.
Choose ChaCha20-Poly1305 or XChaCha20-Poly1305.
Enter the key and nonce, optional AAD, and matching KDF settings if used.
Choose Append Tag or enter a detached 16-byte Authentication Tag.
Decrypt; authentication failures surface as a decrypt error.
Matching parameters
ChaCha20-Poly1305 uses a 96-bit nonce; XChaCha20-Poly1305 uses a 192-bit nonce. Wrong key, nonce, AAD, or tag fails verification. Tag length is fixed at 16 bytes.
Frequently asked questions
Why do I get a bad decrypt error?
Confirm algorithm, key or KDF settings, nonce, AAD, salt format, and whether the tag is appended or detached. Any mismatch fails authentication. OpenSSL-formatted passphrase ciphertext carries the salt in its Salted__ envelope; Format None requires the same salt to be entered separately.
Input
Drag and drop the file here, click to select, or paste from the clipboard. It will process locally and won't be uploaded.
