It happens in your browser
The cryptography runs entirely on your device using the browser's built-in Web Crypto engine. Nothing to encrypt is ever uploaded — there's no server-side copy to leak, subpoena, or lose.
Domainless · Encryption
Encryption that never leaves your device.
Lock text and files with a passphrase, share a secret that burns after one read, or send a message only one person can open. Every byte is encrypted right here in your browser — the server never sees your passphrase, your keys, or a single line of what you wrote.
Checking service…Zero-knowledge by design
For one-time secrets, only unreadable ciphertext is stored. The key travels inside the link itself, in the part browsers never send to a server. We couldn't read your secret if we wanted to.
Standard, audited crypto
AES-256-GCM with PBKDF2 key stretching — the same primitives that secure banks and password managers. No home-rolled ciphers, no obscurity. The whole method is written out on the How it works page.
Three tools, one principle
Whatever you need to protect, the private part stays with you.
Encrypt & decrypt
Lock any text or file with a passphrase. Share the result over email, chat, anywhere — it's useless without the passphrase, which you send separately.
Open the tool →One-time secret
Turn a password or note into a link that self-destructs after it's read once. Perfect for handing someone a credential without leaving it in their inbox forever.
Create a link →Key exchange
Generate a keypair, publish the public half, and let anyone send you a message only your private key can open — no shared passphrase to agree on first.
Make a keypair →How a passphrase lock works
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1
You type, your browser stretches
Your passphrase is run through PBKDF2 — 250,000 rounds of hashing — into a 256-bit key. The stretching makes brute-forcing a weak passphrase far slower for an attacker.
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2
The data is sealed with AES-256-GCM
A fresh random salt and nonce go into every operation, and GCM adds an authentication tag — so any tampering with the ciphertext is detected instead of silently decrypting to garbage.
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3
You share the block and the passphrase apart
Send the encrypted block however you like; deliver the passphrase through a different channel. Neither half is useful alone, and the server was never in the loop.
What our server can and can't see
The honest inventory. This is the whole reason to encrypt on the device instead of on a server you have to trust.
Your passphrase
Never sent. It stays in the page.
Your text & files
Never uploaded. Encryption is local.
Your keys
Never leave the browser.
One-time secrets
Only ciphertext it can't read is stored, then burned.
Who you are
No account. Just a short-lived rate-limit counter.
The safest copy of this tool is your copy
Here's the uncomfortable truth about every "client-side" web tool, ours included: your browser runs whatever code the server sends that day. If we were hacked, coerced, or turned bad, the page could change and you'd never know. So our standing recommendation is the opposite of lock-in — don't rely on us. Take a copy you control, verify it once, and it can never change under you. Nothing you encrypt depends on this website existing, either.
Offline app
One self-contained HTML file that encrypts and decrypts everything — keep it with your backups.
Full source code
MIT licensed, with a manual, a command-line tool, and instructions to run your own copy.
Frozen formats
Byte-exact spec; the original app stays online unchanged at /files/encrypt/legacy/.