Text Encryption Online Free — AES-GCM 256-Bit Encrypt & Decrypt in Your Browser

This online text encryptor uses AES-GCM (Advanced Encryption Standard — Galois/Counter Mode) with a 256-bit key. Your passphrase is stretched through PBKDF2 with SHA-256 and a random salt to produce a strong key. AES-GCM 256-bit encryption is an authenticated cipher, meaning it protects against both eavesdropping and tampering. It is the same algorithm used to secure HTTPS connections and is approved by NIST for top-secret data.

Yes. Text encryption online free means exactly that — there is no cost, no account, no subscription, and no email required. Open the page, paste your text, enter a passphrase, and click Encrypt. All processing happens in your browser using the native Web Crypto API. There are no usage limits, no premium tiers, and no ads that gate features. The tool will always be free and open to use instantly.

No data leaves your device at any point. This is a fully client-side encryption tool — your plaintext, your secret passphrase, and the resulting ciphertext are all processed locally by your browser's built-in Web Crypto API. No network requests are made during encryption or decryption. The server never sees your input. This makes it safe even for sensitive content such as passwords, private notes, or confidential messages.

AES-GCM 256-bit is an authenticated encryption mode, which means it simultaneously encrypts your data and produces an authentication tag. This tag ensures that the ciphertext has not been altered during storage or transit. Many older tools use AES-CBC without authentication, which is vulnerable to padding-oracle attacks. AES GCM 256-bit is the modern standard recommended by security researchers, used in TLS 1.3, SSH, and end-to-end encrypted messengers. This tool uses it properly with a random IV and PBKDF2 key derivation.

There is no way to recover the original text without the exact passphrase. AES-GCM encryption is computationally infeasible to break by brute force with a 256-bit key — even with all the computing power available today, cracking it would take longer than the age of the universe. This also means UtilityBox cannot help you recover data. Store your passphrase safely — a password manager is a good place to keep it alongside the ciphertext.

Yes. Switch to the Decrypt tab, paste the Base64-encoded ciphertext that was produced during encryption, enter the same passphrase, and click Decrypt. The tool will reconstruct the original plaintext instantly in your browser. Decryption also runs entirely client-side with no server involvement. If the passphrase is wrong or the ciphertext has been modified, decryption will fail and you will see an error — this is the authentication tag doing its job.

Yes. The online text encryptor handles any length of input — short passwords, long paragraphs, entire documents, JSON blobs, or code snippets. It also correctly handles all Unicode characters including emoji, Arabic, Chinese, Hindi, and other scripts. The output is a Base64 string safe to copy, paste, email, or store in any text field. There are no character or size limits imposed by the tool itself; practical limits come from your browser's memory.

Base64 encoding is not encryption — it is a reversible encoding that anyone can decode without any key. AES encryption online, by contrast, uses a secret passphrase to scramble data so that only someone with the correct key can reverse it. If you want to protect sensitive information, you need encryption, not encoding. Use this text encryption online free tool to secure secrets. Use the Encoder / Decoder tool on UtilityBox for Base64 or URL encoding where security is not required.