How to Password-Protect Archives: 7Z and ZIP Encryption Compared
Add AES-256 password protection to your archives in the browser - which formats support it, how header encryption works, and what to avoid.
ilove7z Team · Oct 4, 2026 · 4 min read
Password protection turns an archive from “locked folder” into something genuinely private. Here is how the two formats with real encryption support work, and where the traps are.
Which formats support encryption
| Format | Contents encrypted | File names encrypted | Algorithm |
|---|---|---|---|
| 7z | Yes | Optional (header encryption) | AES-256 |
| ZIP (AES) | Yes | No | AES-256 |
| ZIP (ZipCrypto) | Yes | No | Legacy, broken |
| TAR family | No | No | None |
Only 7Z and ZIP can be encrypted on this site - and the winner on privacy is clearly 7Z, because it can hide not just the contents but the list of file names too.
Encrypting a 7z archive
- Open the 7Z compressor.
- Drop in the files or folders you want to protect.
- 7Z is pre-selected as the output format.
- Enter your password twice in the options panel and tick encrypt file names if you want the listing hidden.
- Compress and download.
Everything runs locally: the AES-256 encryption is applied by WebAssembly code in your browser, and neither the archive nor the password is ever transmitted. For the background on how the protection works internally, see the guide to 7z AES-256 encryption.
What makes a good password
- Length beats cleverness. Four random words beat a short string of symbols.
- Unique per archive. Never reuse the password from your email or any account.
- Share it through a different channel. Sending the archive and the password in the same email defeats the purpose - use a second channel (phone call, messenger).
ZIP encryption warnings
Two traps to know about:
- ZipCrypto, the classic ZIP password, is broken. Free tools can remove it in seconds. If your tool offers no AES option for ZIP, treat the password as cosmetic.
- Compatibility cuts both ways. AES-encrypted ZIP opens everywhere only if the recipient’s tool supports AES; the built-in Windows extractor does not. When in doubt, use 7z and tell the recipient to open it with 7-Zip or extract it in the browser.