Vernam
VERNAM encrypts files in the browser; its project says processing happens client-side and files are not uploaded.
About Vernam
VERNAM is a browser-based file encryptor that processes files client-side. Users drop in a file and set a passphrase to encrypt it, then drop in the encrypted file and enter the passphrase to get the original back.
The project states that nothing is uploaded, no account is required, and it can work offline. It uses Argon2id for key derivation and XChaCha20-Poly1305 via libsodium secretstream, with per-chunk authentication. There is no recovery if the passphrase is forgotten. Streaming to disk for large files uses the File System Access API in Chromium-based browsers; Firefox and Safari use in-memory download capped at 2 GiB.
Key features
- Encrypt files in browser by setting a passphrase
- Decrypt by re-adding encrypted file and entering passphrase
- Client-side processing with project stating no uploads
- Argon2id key derivation to 256-bit key
- XChaCha20-Poly1305 streaming encryption via libsodium
- Built-in passphrase generator
Best for: People who need to encrypt files locally in a browser without creating an account.
Good for
- Project states files are processed client-side with no uploads or servers
- No account, sign-up, email, or tracking required according to project
- Can be self-hosted as static files with no backend
Watch out for
- No backdoor or recovery; forgotten passphrase means file cannot be recovered
- Firefox and Safari fall back to in-memory download capped at 2 GiB
- Opening index.html as file:// does not work due to browser blocks
Vernam at a glance
- Category
- Software & Utilities › File Utilities
- Type
- Open-source project
- Pricing
- Not confirmed. Check the site
- Open source
- Not stated
- Language
- English
- Last checked
- Oct 5, 2026 · Online when checked
- Listed
- Oct 5, 2026
Guides for File Utilities
Vernam alternatives
Tools and sites you could use instead, ranked by how closely they match.
VeraCrypt provides disk encryption and publishes source code based on TrueCrypt 7.1a with security enhancements and modifications.
Cryptomator provides client-side encryption for cloud storage on Windows, macOS, and Linux, according to its project page.
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VERNAM encrypts files in the browser using a passphrase and supports opening .vrn files, according to its page.
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Picocrypt-NG encrypts files, with its project describing the tool as small and simple.
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Encrypt files with age, a tool and Go library that uses small explicit keys and avoids configuration options.
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Encrypt files for cloud storage with Cryptomator, an open-source tool listed for services including Dropbox and Google Drive.
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13 alternativesPopular in File Utilities
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Vernam FAQ
What happens if I forget my passphrase?
The project states there is no backdoor and no recovery, so the file cannot be recovered.
Can I run my own copy?
Yes, it can be served locally or on a static host as static files, with the condition to keep a visible working link to PrivacyTools.io.
How are large files handled?
Large files stream to disk in Chromium-based browsers; Firefox and Safari use in-memory download capped at 2 GiB.
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