Many online file-encryption or password-protection tools ask you to upload your file to a server first — which means trusting a stranger's server with the exact file you're trying to protect. NearSeal encrypts entirely on your device using your browser's built-in cryptography; the unprotected file never leaves your browser.
→ 0 files sent to a server · encryption runs on your device
Putting a password on a ZIP archive or an Office document is the most common way to protect a file — but the strength varies wildly: the legacy ZipCrypto scheme many ZIP tools still default to is decades old and practically breakable, and passwords on old .doc/.xls files are weaker still. NearSeal seals any file type with modern authenticated encryption (AES-256-GCM by default, or the open age standard), so without the passphrase the contents can't be read or silently tampered with — and it all happens in your browser, so the file and passphrase never leave your device. It does exactly one thing: encrypt and decrypt with a passphrase you keep. There is no password recovery, no key sharing, and no cloud copy — if you lose the passphrase, the file stays sealed.
A password-protected ZIP has two classic weaknesses: many tools still default to the ancient ZipCrypto scheme, which can be broken with commodity software, and even a well-encrypted ZIP leaves the list of filenames inside readable to anyone, because the archive’s table of contents is not encrypted. Office passwords are inconsistent across eras too — modern .docx encryption is reasonable, but the older .doc/.xls schemes are trivially cracked, and either way they only cover Office documents. NearSeal applies the same modern authenticated encryption (AES-256-GCM, or the open age standard) to any file type, and a sealed file reveals nothing about its contents.
The workflow trade-offs are worth knowing before you choose. A sealed file is not a ZIP: the recipient opens it on this page (free, no account, no install) or with an age-compatible tool if you chose that format — not by double-clicking in a file manager. And there is deliberately no recovery path: no upload also means no server-side reset, so a forgotten passphrase cannot be restored by anyone, including us. For files whose loss would hurt more than their exposure, keep the passphrase in a password manager.
No. NearSeal encrypts your file locally, using the Web Crypto API built into your browser (AES-256-GCM). A strict Content-Security-Policy technically blocks any request that could send your file or passphrase anywhere.
AES-256-GCM with a passphrase-derived key by default, or the open age-encryption.org standard as an opt-in — so a sealed file can also be opened with any other age-compatible tool later, not just NearSeal.
Sometimes. If both sides use AES-256 ZIP encryption and you only need to hide the contents, it can be — but many tools still default to the breakable legacy ZipCrypto, an encrypted ZIP still exposes the filenames inside it, and the recipient’s tool has to support the same scheme. NearSeal removes those variables: one modern authenticated format for any file type, encrypted without the file ever leaving your device.
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