Frequently asked questions

No. Everything runs in your browser. The archive is read locally with the File API and parsed on the page, and Web Workers test passwords against the bytes of one encrypted entry from it. See the security & privacy page.

No. Candidate and recovered passwords stay inside your browser tab. A recovered password is displayed only to you and copied only when you choose to.

Because the file never leaves your device, the tool does not expose your archive to a third party. As always, use a device and browser you trust.

Two things, and neither leaves your device. A ZIP you drop or choose on the home page waits in your browser's storage until the recovery page opens it and deletes it. A mask or brute-force search saves its progress as it runs, with the file's name and size and your search settings (which can include a mask you typed), so you can continue after a reload or after closing the tab; that record is deleted when the search finishes, when you press Stop, or when you choose Start fresh. Dictionary searches are never saved. The privacy policy has the details.

Your browser downloads pages and scripts as on any site. The only data the site sends back is an anonymous error report if its own code fails: the error type and message, the stack trace, the script address with its line and column, the page path, the page language, your browser's user agent, the time, the site's release, and, for a failure inside the recovery tool, a one-word label for the part that failed. It never includes your archive, file names, or any password, and reports are kept for up to 90 days. See section 4 of the privacy policy.

Traditional ZipCrypto (PKWARE) and WinZip AES-128/192/256. The tool detects the method automatically. Read about ZipCrypto and AES.

A dictionary of likely passwords (with optional common variations), a mask that describes the password's shape, or a bounded brute-force search over a character set.

Yes. Recovery runs off the main thread, so you can pause, resume, or stop at any time and the page stays responsive. Pause keeps a mask or brute-force search's progress on this device, so you can continue later, even after a reload; Stop ends the search and deletes that progress.

Current versions of Chrome, Edge, Firefox, and Safari that support WebAssembly and Web Workers. Our end-to-end tests drive the tool in Chromium, and on 27 September 2026 they also ran it in Firefox and WebKit (the engine behind Safari), on desktop; in WebKit a file dropped on the home page did not reach the recovery page, so in Safari Private Browsing choose the file on the recovery page; phones and tablets are not part of those tests. The tool checks compatibility when you open it.

The search runs on your device. Our end-to-end test watches every request from opening the recovery page to the unlocked file: nothing goes to another site and your archive is never uploaded. During a run the page can still fetch its own files from this site, such as the script each worker loads, and a failure of the site's own code sends an error report, never file data or passwords. We have not tested a run with the connection cut: opening the page needs a connection, and the optional file-decryption feature loads a small additional library on first use.

No. Recovery depends on the password's length and randomness and on the encryption method. Strong, random passwords, especially on AES archives, are effectively not recoverable by guessing.

WinZip AES runs PBKDF2 with 1000 iterations of HMAC-SHA1 per candidate on purpose. That deliberate slowdown is a security feature and limits how many candidates can be tried per second.

Rarely, and how rarely depends on the archive. For AES the stored HMAC makes a wrong password effectively impossible to report. For a ZipCrypto entry of at least 4 bytes that is stored or compressed with Deflate, a reported password has passed decryption and the CRC-32 on top of the fast header filter, which a wrong password clears about once in 2^40 candidates, roughly 1 in 1.1 trillion. Long searches do run past that many: the illustrative 8-character model on how long recovery takes is about 2.8 trillion candidates. So open the archive with the reported password rather than treat it as proof. ZipRecover cannot confirm at all in one rare ZipCrypto case: when every protected file small enough to check in the browser (256 MB compressed) is a ZipCrypto file that is tiny (under 4 bytes) or uses another compression method, such as BZip2, LZMA, or Deflate64 (options in tools like 7-Zip). With those other methods a search usually ends without a match. The result then says the password passed only a quick check.

Then there is no password to recover, and you can open it with your operating system's built-in ZIP tools.

It is intended only for archives you own or are explicitly authorized to access. Using it on files without authorization may be illegal. See the Acceptable Use Policy and Terms of Use.

No. The confirmation is a product safeguard, not legal advice, and it does not grant any rights or guarantee any legal protection.