Encrypt Text & Decrypt Text Online — Free AES Text Encryption Tool

Encrypt Text & Decrypt Text Online — Free AES Text Encryption Tool. Free online text encryption: encrypt and decrypt text with a secret key using AES-256, TripleDES, Rabbit or RC4. Base64 or hex output, OpenSSL-compatible, 100% in your browser.

Our free online text encryption tool lets you encrypt text and decrypt text with a secret key in one page.

Type a message, choose a passphrase and an algorithm — AES (AES-256 in CBC mode with PKCS#7 padding), TripleDES (3DES-CBC with a 192-bit key), the Rabbit stream cipher or RC4 — and the ciphertext updates instantly.

Paste it into the decrypt panel (or click "Decrypt this") with the same key and algorithm to get the original text back.

Output can be Base64 or hex, and the decrypt side detects the format automatically, which makes it a convenient AES encryption online and AES decrypt online tool for developers, students and anyone who wants to protect a short note.

Under the hood the tool uses the CryptoJS library in passphrase mode: a random 64-bit salt is generated for every encryption and the key and IV are derived with OpenSSL's EVP_BytesToKey (MD5, one iteration).

The result uses the OpenSSL Salted__ format (Base64 starts with U2FsdGVkX1), so it is compatible with CryptoJS code such as CryptoJS.AES.decrypt(ciphertext, passphrase) and with openssl enc -d -aes-256-cbc -md md5 -a.

Because the same text encrypts differently every time, identical messages are not revealed. This key derivation is fast, so security depends on a strong secret: use the Generate random key button or our Passphrase Generator.

TripleDES and RC4 are legacy ciphers kept for compatibility — prefer AES for new data, and note that encryption is not authenticated (no integrity tag). Everything happens locally in your browser — your plain text and secret keys are never sent to a server.

A wrong key or algorithm is reported as a decryption error instead of silently showing garbage for AES and TripleDES.

You can copy the encrypted or decrypted text in one click, and share a link that contains only the ciphertext and algorithm (never the key or the plain text). Need one-way hashing instead of reversible encryption?

Try Hash Text, the HMAC Generator or Bcrypt; for public-key cryptography use the RSA Key Pair Generator, and for simple encoding see the Base64 String Converter.

Frequently asked questions

How do I encrypt and decrypt text with this tool?

In Encrypt, enter your text and a secret key, choose an algorithm (AES is the default and recommended; TripleDES and RC4 are legacy) and Base64 or hex output, then copy the encrypted text. To decrypt, paste it into the Decrypt section with the same key and algorithm; the Decrypt this button does it in one click.

Which AES mode and key derivation does the tool use?

AES is AES-256 in CBC mode with PKCS#7 padding, via the CryptoJS library. For each encryption a random 8-byte salt is generated and the key and IV are derived from your passphrase with OpenSSL's EVP_BytesToKey (MD5, one iteration). The output uses the OpenSSL Salted__ format, so Base64 results start with U2FsdGVkX1.

How secure is it, and why does my passphrase matter?

AES-256 itself is strong, but the key is derived from your passphrase with a single fast MD5 round, so a short or common passphrase can be guessed by brute force. Use Generate random key or a long random passphrase and share it through a separate channel. The ciphertext has no authentication tag, so tampering is not detected.

Can I decrypt the result with OpenSSL?

Yes, for AES. Save the Base64 output on one line to a file and run openssl enc -d -aes-256-cbc -a -A -md md5 -in file.txt, then enter the same passphrase. The -md md5 option is needed because OpenSSL 1.1.0 and later use SHA-256 for key derivation by default.

Why does decryption fail with an error?

Decryption fails when the secret key or algorithm is different from the ones used to encrypt, or when the ciphertext was cut off or changed. Keys are case-sensitive. Base64 or hex input is detected automatically, so you do not need to choose a format when decrypting.

Is my text or secret key sent to a server?

No. Encryption and decryption run in your browser. The Share ciphertext link contains only the encrypted text and the algorithm, never your secret key, so send the key separately.

How to use this online tool

Encrypt Text & Decrypt Text Online — Free AES Text Encryption Tool is designed for fast browser workflows when you need to format, validate, convert, decode, encode, generate, or inspect data without opening a heavy desktop app. Start with the input field or visible options, review the result, then copy or download the output for the next step.

Private processing in your browser

Encrypt Text & Decrypt Text Online — Free AES Text Encryption Tool keeps the normal processing step local in your browser. That is useful for code snippets, tokens, documents, configuration values, text samples, and other material that should not be sent to a remote service unless you explicitly choose to share it.

When this tool is useful

Use Encrypt Text & Decrypt Text Online — Free AES Text Encryption Tool for repeatable developer tasks, technical documentation, QA checks, quick conversions, debugging, content cleanup, and internal team workflows. The page focuses on clear inputs, immediate feedback, and output that is easy to reuse in code, reports, tickets, emails, or notes.

Practical tips

Before copying the final result, check important details such as spacing, casing, filenames, encoding, token structure, line breaks, or output format. Small checks prevent mistakes when the result is reused in source code, API requests, documentation, spreadsheets, or shared files.