ManyEditHow to Protect a Note With a Passphrase
Guide ยท about 5 minutes to read
You may want to keep a note, a password reminder or a private message readable only by you, or by someone you trust. Encryption does this by scrambling the text with a secret key. Only someone with the passphrase can turn it back into readable text.
How passphrase encryption works
The encrypt and decrypt tool uses AES-256-GCM, a widely used standard. Your passphrase is stretched into a key using PBKDF2, which makes guessing it slow. Each encryption also uses a random salt and starting value, so the same note encrypted twice gives different output.
The result is a single line of letters and numbers. You can paste it into a message, a document or a file.
Choose a strong passphrase
Your passphrase is the only thing protecting the text, so it matters more than the tool. Use four or more random words, or a long sentence that only you would write. Length matters more than symbols. Don't reuse a passphrase from another account.
Encrypt a note
- Open the encrypt and decrypt tool and choose Encrypt.
- Type your passphrase. Tick Show passphrase to check it, then untick it.
- Paste your note into the input box and press the button.
- Copy the result and save it where you need it.
Decrypt it later
Open the same tool, choose Decrypt, enter the passphrase and paste the encrypted text. If the passphrase is right, the original note appears. If it's wrong, the tool shows an error and no text.
Keep it safe
- Write the passphrase down somewhere separate from the encrypted text. Without it, the note can't be recovered.
- Don't share the passphrase in the same message as the encrypted text.
- Keep a plain copy only if you're sure it's safe, because encryption protects the stored text, not the device it sits on.
What encryption doesn't do
Encryption protects content, not everything around it. Someone who can see that you sent a message, or who can see your screen while you type, may still learn things. For high-stakes information, use a dedicated password manager or a tool reviewed for your specific needs.