How to use the Text Encryptor
Last verified 2026-08-09 · about 7 minutes to read
The short version
- 1.Enter your text and a passphrase. Use a long, random passphrase — the algorithm is strong, but it can only ever be as strong as what you type here.
- 2.Press Encrypt. Key derivation runs 600,000 rounds and takes a moment. That delay is the point: it is what makes guessing the passphrase slow for an attacker too.
- 3.Send the whole block. The output contains the salt and nonce it needs to decrypt. Copy all of it — a truncated block cannot be recovered.
Why this is worth getting right
Competitor research on this keyword found the same three mistakes repeatedly, each fatal: the passphrase used directly as the key, unauthenticated CBC or ECB mode, and a fixed or missing IV. This implementation derives the key with PBKDF2 at the OWASP-recommended work factor, uses authenticated AES-GCM, and generates a fresh random nonce for every message.
Method 1 — use the Text Encryptor on this site
The fastest route. It runs entirely in your browser, so nothing is uploaded and there is no queue to wait in. No account is needed and there is no daily limit.
- Enter your text and a passphrase. Use a long, random passphrase — the algorithm is strong, but it can only ever be as strong as what you type here.
- Press Encrypt. Key derivation runs 600,000 rounds and takes a moment. That delay is the point: it is what makes guessing the passphrase slow for an attacker too.
- Send the whole block. The output contains the salt and nonce it needs to decrypt. Copy all of it — a truncated block cannot be recovered.
Method 2 — do it without this site
Worth knowing, because a tool you cannot replace is a dependency rather than a convenience. Most tasks in the text division have a command-line or built-in equivalent; it is usually more setup and less convenient, but it works offline and it is scriptable, which matters once you are doing something a hundred times instead of once.
What this tool will not do
Every tool has an edge. These are ours for text encryptor, stated up front so you find out here rather than halfway through a deadline:
- The passphrase is the whole security boundary. A weak one defeats every parameter in the table above.
- There is no key recovery. Lose the passphrase and the text is gone permanently.
- This is not a password manager and not a file encryptor. Use a password manager for credentials, and age or GnuPG for files.
- It protects the message in transit or at rest. It does nothing about a compromised device.
Common problems and how to fix them
- Decryption failed: wrong passphrase, or the encrypted text was altered
- GCM cannot tell those two apart — both fail authentication identically. Check the passphrase first, then check the whole Base64 block was copied, including the last line.
- That encrypted block is too short to be valid
- Part of it was lost in copying. The block contains a version byte, a 16-byte salt, a 12-byte nonce and a 16-byte tag before any message content.
Questions people ask
Is my text sent to a server?
No. Encryption and decryption both run in this browser tab through the Web Crypto API. You can load the page, disconnect from the internet, and it still works. For this tool in particular that is not a convenience — a text encryptor that uploads your plaintext is worse than useless.
What encryption does this use?
AES-256 in GCM mode. The key is derived from your passphrase with PBKDF2-HMAC-SHA256 at 600,000 iterations and a fresh 16-byte random salt, which is the current OWASP recommendation. Each message gets a new 12-byte random nonce.
Why does encrypting take a second?
Because of the 600,000 key-derivation rounds. That is deliberate. A fast key derivation is a fast dictionary attack — the delay you experience once is a delay an attacker experiences on every single guess.
What happens if I lose the passphrase?
The text is unrecoverable. There is no reset, no backup and no recovery key, because there is no account and no server. That is a consequence of the design, not an oversight.
Can someone modify the encrypted text without me knowing?
No. GCM is an authenticated mode: it produces a 128-bit tag over the ciphertext, and decryption fails outright if a single bit has changed. Unauthenticated modes like CBC would return plausible-looking garbage instead.
Should I use this to store passwords or important documents?
No. Use a password manager for credentials and a file-level tool like age or GnuPG for documents. This is for sending a short message over a channel you do not trust, where both sides already share a passphrase.
Why is there no API for this tool?
Because an API means sending the passphrase and the plaintext to a server, which removes the only property that makes the tool worth using. It is the one tool on this site deliberately excluded from the API.