Encrypt Text Online Free: Lock a Message With a Passphrase

You can encrypt text online by typing a message and a passphrase into a tool that turns the message into a block of Base64 text that only that passphrase can open. FileReadyNow's free Text Encrypt/Decrypt tool does this with AES, and its page says the work happens in your browser. This guide covers the exact steps, how to pick a passphrase, what the page does and does not tell you, and how to check the privacy claim yourself.

What the Text Encrypt/Decrypt tool does

According to the tool page, it encrypts and decrypts plain text using AES (the Advanced Encryption Standard), combined with a salt and an initialization vector to produce "secure, unique encrypted output." The result is encoded in Base64, which means it comes out as ordinary letters, numbers and a few symbols that you can paste into an email, a chat or a note. Decrypting reverses the process, as long as you supply the same passphrase.

The page says the passphrase is never stored or transmitted, and that your text and passphrase are never sent to any server. It also says there is no length restriction on the text. Here is what you will see on the tool.

How to encrypt text, step by step

1. Open the tool. Go to Text Encrypt/Decrypt and stay on the Encrypt Text tab.
2. Add your message. Type or paste it into Secure Text. Notes, a password you need to pass on, a snippet of code or anything else in plain text all work.
3. Enter a passphrase. Type it into the Secure Pin field. Make it long and unique (more on that below).
4. Click Encrypt Data. The encrypted text appears as one long Base64 string.
5. Copy the result. Use Copy Key to copy the encrypted string, then paste it where you want to keep or send it.
6. Clear the fields. Click Clear All so your plain text and passphrase are not left sitting on the screen.

How to decrypt text

1. Switch tabs. Open the Decrypt Text tab.
2. Paste the encrypted string. Put the whole thing into the Encrypted Key field. Copy it exactly, with no extra spaces or missing characters at the ends.
3. Enter the same passphrase. It has to match what was used to encrypt, character for character.
4. Click Decrypt Data. Your readable message should appear in Secure Text.
5. Copy it if you need it. The Copy button copies the decrypted text.

The page does not say what message you get when the passphrase is wrong, so I will not guess at it. Run one test with a harmless sentence and a deliberately wrong passphrase, and you will know what to expect. To confirm a full round trip, you can paste the decrypted text and your original into the Text Compare tool and check that they match.

Choose a passphrase that is worth the trouble

The tool page recommends a long, unique passphrase and warns that if you lose it, the encrypted text cannot be recovered. FileReadyNow does not keep a copy, so nobody can reset it for you.

My advice, and it is only advice: use several unrelated words instead of one clever word, do not reuse a passphrase from another account, and store it somewhere other than next to the encrypted text. FileReadyNow's Password Generator has a passphrase mode (four words by default, according to its page) and runs in the browser, so it can hand you something suitable.

Send the encrypted text and the passphrase by different routes

Encryption only protects the message if the passphrase stays secret. If you send the encrypted string and the passphrase in the same email or chat, anyone who reads that one conversation can read everything. Send the encrypted text by whatever channel is convenient, and give the passphrase over a phone call, in person, or in a different app. The tool's own FAQ makes the same point in other words: the other person needs both the encrypted text and the shared key.

Check the "nothing is sent" claim yourself

The page says your text and passphrase are never sent to a server. You do not have to take that on trust.

1. Use a harmless test sentence. Something like "this is a test", not a real secret.
2. Open developer tools. In Chrome, press F12 on Windows or Linux, or Cmd+Option+I on a Mac, then open the Network tab.
3. Clear the log. Use the clear button so the list starts empty.
4. Encrypt and decrypt. Run both steps on the tool as usual.
5. Read the requests. Requests for scripts, images or analytics are normal on almost every site. You are looking for a request, usually a POST, that carries your text or passphrase to the site. If you see none, the work happened in your browser.

What AES is, and what the page does not tell you

AES is a standard published by the US National Institute of Standards and Technology. FIPS 197 describes a block cipher that works on 128-bit blocks, in three versions called AES-128, AES-192 and AES-256, where the number is the key length in bits. NIST first published it in November 2001 and last updated it in May 2023.

That tells you what AES is. It does not tell you how this particular tool is built, and the tool page leaves several things unsaid: the key size, the cipher mode, how your passphrase is turned into a key, and how many rounds of key stretching are used. Those details matter for security. If you work with data where they matter, such as customer records or regulated information, do not rely on a small web tool. Use audited software, and follow your organization's rules.

Browsers include a built-in set of cryptographic functions, described in MDN's guide to the Web Crypto API. MDN is blunt that these functions are easy to misuse and that the pitfalls can be subtle. I cannot tell from the tool page whether it uses that API, but the warning is a fair reason to be modest about what any quick encryption tool can promise.

Know the limits

• The page describes the tool as suitable for personal and light-duty use, not enterprise or regulatory needs.
• It works on text. It is not a file encryptor.
• If you lose the passphrase, the text stays locked for good.
• Encryption does not protect what is on your screen, or what is sitting in your clipboard, before you encrypt and after you decrypt.
• Very long text depends on your own device's speed, even though the page says it has no length restriction.

Encrypting text online: questions answered

Can I encrypt text online without sending it to a server?

Yes, if the tool processes your text in the browser. FileReadyNow's Text Encrypt/Decrypt says your text and passphrase are never sent to any server. You can confirm this yourself by watching the Network tab in your browser's developer tools while you encrypt a harmless test sentence.

What happens if I forget the passphrase?

The encrypted text cannot be recovered. The tool page says the passphrase is never stored or transmitted, so FileReadyNow has no copy to give back to you. Keep the passphrase in a password manager or another safe place, and keep it apart from the encrypted text itself.

Can someone else decrypt the text I encrypt?

Yes, but only with the encrypted text and the same passphrase. The encrypted string alone is not readable. Send the passphrase by a different route than the one carrying the encrypted text, such as a phone call, so one stolen message does not give everything away.

Which AES key size does the tool use?

The tool page says it uses AES with a salt and an initialization vector, but it does not publish the key size, the cipher mode or how your passphrase becomes a key. AES itself comes in 128, 192 and 256-bit versions under NIST's FIPS 197 standard.

Is it safe to encrypt passwords or sensitive documents with it?

The page describes the tool as suitable for personal and light-duty use, not enterprise or regulatory needs. It fits private notes or a password you need to hand over. For regulated or high-stakes data, use audited software and follow your organization's rules.

Ready to try it? Open Text Encrypt/Decrypt, encrypt a harmless sentence with a passphrase, and watch the Network tab while you do it. It takes about two minutes, and you will see for yourself what happens to your text.