What is steghide?

steghide is a popular command-line program that hides a whole file inside a JPEG or BMP picture, or a WAV or AU sound file. In a JPEG it nudges some of the numbers the compression stores, spread across the picture in an order that depends on the passphrase. The hidden file is usually compressed and encrypted, so without the exact passphrase there is nothing to see, and the picture looks unchanged.

CacheCrack reads steghide files directly in your browser. Enter the passphrase and it shows the hidden file's name, contents and a download button. It reads steghide's default settings, including its standard AES encryption, and files hidden with no encryption at all.

Don't know the passphrase?

Leave "Also try common passphrases" on and add your own guesses, one per line: words from the cache title, the owner's name, answers to earlier stages. Wrong guesses are rejected in a fraction of a millisecond, so long lists are fine. An empty passphrase is always tried too, since many puzzles use none.

Private and offline

Most online steghide tools upload your file to a server. CacheCrack runs steghide's extraction on your own device, so your file and your guesses never leave it.

Limits

steghide can also encrypt with rarely used ciphers like Blowfish or Serpent. CacheCrack tells you when a file uses one of those, but can only unlock the default AES and unencrypted files. The Image analyzer checks JPEGs and BMPs for steghide automatically using an empty passphrase and common guesses.