BunchTool — ZIP Password Checker
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📁 Target ZIP
0 MB
🔍
Drop your ZIP archive here
or click to browse · Safe local locks parsing
✅ Encryption Analysis
🔍 Upload a ZIP file to analyze its encryption headers and password locks
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🗜️ Zip & Archive Tools

ZIP Password Checker —
Free ZIP Password Checker Online

Check if a ZIP archive is password protected. Detect ZipCrypto or AES-256 encryption type and check password strength. Private and secure.

Check lock encryption status instantly
Zero server uploads — 100% browser processing
Works offline once the page has loaded
Differentiate ZipCrypto vs high AES-256
🔍
FreeAlways
FreeAlways
BrowserComputed
How It Works

Use ZIP Password Checker in three steps

Step 1
📂
Select Target ZIP

Type or paste your password into the input checker field.

Step 2
⚙️
Detect Encryption

View real-time feedback on entropy, crack time, and strength metrics.

Step 3
⬇️
Download your result

Get secure recommendations for making your ZIP files uncrackable.

Why BunchTool

Why use our free ZIP Password Checker?

🔒
Zero server uploads

Your data is processed entirely inside your browser using client-side JavaScript. Nothing ever travels over a network to any server — making BunchTool the most private option available.

Instant local processing

Because everything runs locally in your browser, there are no upload queues or server wait times. Results appear in seconds regardless of your internet speed — or even without any connection at all.

💪
Entropy Strength Audit

Validate the resistance of your passwords against brute force and dictionary attacks. Secure your data with reliable mathematical feedback.

FAQ

Frequently asked questions

Is the ZIP Password Checker free to use?
Yes — completely free with no file-size limits, no daily usage caps and no premium tier. All 247 tools on BunchTool are free forever, with no upsells or paywalls.
Is my data safe and private?
Absolutely. Your data is processed entirely inside your browser using client-side JavaScript. Nothing ever leaves your device or is uploaded to any server.
Does the ZIP Password Checker work offline?
Yes. Once this page has loaded in your browser, the tool continues to work without an internet connection. Your browser handles all the processing locally on your device.
How does the tool check for passwords without uploading?
Every file inside a ZIP archive has a 2-byte General Purpose Bit Flag in its local header. Bit 0 specifies if the file is encrypted. Our client-side JS reads these header flags locally to verify lock status instantly.
Does this tool brute-force ZIP passwords?
No, brute-forcing a secure ZIP archive (especially AES-256) inside a browser is computationally unfeasible. The tool detects the encryption parameters and allows you to test passwords in your browser safely to verify if they unlock the files.
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