100% Client-Side

AES Decryption Tool

Free online AES decryption tool. Decrypt AES-128, AES-192, or AES-256 ciphertext with CBC, ECB, CTR, OFB, and CFB modes directly in your browser. — runs 100% in your browser, client-side only. No data is sent to any server. Free to use, no account required.

Free Client-Side No Login No Storage
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AES Encryption Tool Encrypt text with AES-128, 192, or 256-bit keys — 100% client-side HMAC Generator Generate HMAC message authentication codes — SHA256, SHA512, SHA1, MD5 RSA Key Pair Generator Generate RSA public & private key pairs — 1024, 2048, or 4096-bit

How to Use the AES Decryption Tool

  1. Paste the AES ciphertext you want to decrypt.
  2. Select the key size (128, 192, or 256-bit) used during encryption.
  3. Choose the mode (CBC, ECB, CTR, OFB, or CFB) — must match encryption mode.
  4. Enter the secret key and IV used during encryption.
  5. Click Decrypt to recover the plaintext.

All decryption runs 100% in your browser using CryptoJS.

What is AES Decryption Tool?

AES decryption reverses AES encryption, converting ciphertext back to readable plaintext using the same secret key and mode (CBC, GCM, etc.) that was used for encryption. AES is a symmetric algorithm — the same key encrypts and decrypts.

Why Use This Tool

When you receive AES-encrypted data from APIs, files, or databases, you need the original key to recover the plaintext. AES decryption is essential for reading encrypted secrets, configs, or protected communications.

When to Use It

Use AES decryption when recovering data encrypted with AES, decrypting API responses, unlocking encrypted config files, or testing encryption implementations during development.

Who Should Use It

Backend engineers debugging encrypted payloads, DevOps teams handling encrypted config values, incident responders validating secure backups, and learners exploring real-world cryptography workflows.

How to Use the AES Decryption Tool

  1. Paste the encrypted payload exactly as generated by your encryption workflow.
  2. Enter the same key, mode, and IV/nonce that were used during encryption.
  3. Run decryption and verify the output matches expected plaintext.
  4. If decryption fails, recheck encoding, key length, mode, and IV format first.

Security note

Never test production secrets in third-party tools unless processing is fully client-side. Keep decryption keys in a secrets manager and rotate keys if accidental exposure is suspected.

Common Uses

  • Decrypting AES-encrypted API responses
  • Recovering encrypted configuration data
  • Testing encryption implementations

Frequently Asked Questions

What do I need to decrypt AES?

You need the exact key used for encryption, the same mode (CBC, GCM, etc.), and for CBC mode, the IV (initialization vector). Without any of these, decryption fails.

Why does my decryption return garbage?

Common causes: wrong key, wrong mode, missing or incorrect IV, or the data wasn't AES-encrypted. Ensure all parameters match exactly what was used for encryption.

Is AES decryption safe in a browser?

Yes. CipherKit uses the Web Crypto API and runs entirely in your browser. Your key and data never leave your device.