AES Encryption / Decryption
Encrypt and decrypt text using AES encryption
Encrypt and decrypt text with AES safely in your browser
AES (Advanced Encryption Standard) is the symmetric cipher trusted by governments, banks, and TLS itself. This tool runs AES entirely in the browser, so the plaintext, ciphertext, and key never leave your device. Use it to wrap small secrets such as configuration values, tokens, personal notes, and snippets you want to share over an insecure channel after agreeing on a key out of band. The page supports common modes and key sizes used in real production code so you can verify outputs against your application before deploying.
- Choose the cipher mode and key length you actually use in your application code (CBC and GCM are the most common; 128-bit and 256-bit keys are the most common).
- Paste your plaintext for encryption or your Base64/Hex ciphertext for decryption.
- Provide the same key (and IV/nonce, if your mode requires one) that the receiving system expects, then run the operation.
- Copy the result, then test it end-to-end against the consuming code path before relying on it in production.
Where AES fits in engineering work
AES is excellent for protecting small sensitive values such as config secrets, exported snippets, and test material shared over an insecure channel after agreeing on a key out of band. The algorithm is mature. The usual failures are operational: weak key handling, IV reuse, wrong cipher mode, or missing integrity protection.
That is why the text around an AES tool matters. Without it, users can easily confuse "the text was encrypted" with "the system is secure." Those are not the same statement.
Why GCM is usually the safer default
If your stack supports it, GCM is normally the better default because it provides confidentiality and integrity together. CBC can still be used, but only with an additional MAC or authenticated design. Using CBC alone because it "still decrypts" is not enough.
The browser tool is best used as a validation aid for formats, encodings, and parameters. Production-grade key lifecycle management still belongs in KMS, Vault, or your platform secret manager.
Best use cases
- Verifying that a backend AES implementation matches the format produced by frontend or mobile clients.
- Encrypting small configuration values or notes before storing them in a shared document.
- Decoding test fixtures and sample ciphertexts during debugging or incident review.
Common mistakes to avoid
- Reusing the same IV with the same key in CBC or GCM mode breaks confidentiality. Generate a fresh IV for every message.
- Storing the key next to the ciphertext defeats the purpose. Treat keys like passwords and store them separately, ideally in a secrets manager.
- AES alone does not authenticate the message in CBC mode. If you need both confidentiality and integrity, prefer GCM or pair CBC with an HMAC.
Related tools
Move directly into the next step instead of leaving the site to do adjacent work elsewhere.
Hash Generator
Compute MD5, SHA-1, SHA-256, SHA-384, and SHA-512 hashes of text or files. Also supports HMAC.
JWT Decoder & Security Auditor
Decode and inspect JSON Web Tokens with client-side security checks for none algorithm, expiry, audience, issuer, and risky claim setups.
Base64 Encoder / Decoder
Encode and decode text or files using Base64 encoding
UUID / ULID Generator
Generate UUIDs (v1, v4, v7) and ULIDs in bulk. UUID v7 is timestamp-prefixed and lexically sortable — great for database keys.
FAQ
Is AES safe enough for production?
Yes. AES-128 and AES-256 with proper modes are widely deployed and have no known practical breaks. The risk is almost always in how the key, IV, and padding are handled, not in the algorithm itself.
CBC or GCM, which mode should I use?
GCM if both sides support it. GCM provides authenticated encryption out of the box, while CBC requires a separate MAC to prevent tampering.
Are my key and plaintext sent to a server?
No. This page performs encryption and decryption inside your browser using crypto-js. The data never leaves your device unless you copy it out yourself.