Free Online AES Decryption Tool - Military-Grade Symmetric Decryption
Free online AES decryption tool for secure data recovery. Decrypt confidential information protected with cryptographically secure AES-128 and AES-256 symmetric decryption. Support for multiple cipher modes including CBC, GCM, and CTR. Ideal for recovering encrypted passwords, API keys, sensitive documents, and protected files. Advanced encryption standard decryption for enterprise security.
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How to Use Free Online AES Decryption Tool - Symmetric Decryption Guide
Master military-grade cryptographic data recovery with advanced encryption standard decryption techniques
Input Your Encrypted Data
Paste your encrypted data here. It should be in Base64 format (that's what you get after AES encryption). Here are a few ways to get started:
Example: Base64-Encoded Encrypted Data
Here's what encrypted data looks like in Base64 format:
Encrypted with block cipher mode:
U2FsdGVkX1+KlHnPEjWQvLNz8xKa8X1wK3qZrVmP2lY=AAAA/QAAA/8AAAA/QAAAf0AAAP8AAAD/AAAA/0AAAP8AAAD/
Provide Decryption Key and Settings
You'll need the same key, IV (Initialization Vector), and cipher mode that were used to encrypt the data. Think of it like needing the right key to unlock a door - everything has to match:
Example: Decryption Settings
Settings must match the original encryption:
Download or Copy Decrypted Data
Once decrypted successfully, your original data will appear in the output section. You can now export it:
Frequently Asked Questions
How do I decrypt AES-encrypted data?
To decrypt AES-encrypted data, you need the exact same key, IV, and cipher mode that were used during encryption. Paste your Base64-encoded encrypted data into the input field, provide the key and IV in hexadecimal format, select the correct AES mode and cipher mode, and the tool will automatically decrypt your data.
What's the difference between AES-128 and AES-256?
The numbers refer to the key size: 128-bit and 256-bit respectively. AES-256 provides stronger security with a larger key. When decrypting, you must use the same AES mode that was used for encryption, otherwise decryption will fail.
What do I do if decryption fails?
Decryption failure usually means one of these: wrong encryption key, incorrect IV, mismatched AES mode (128 vs 256), mismatched cipher mode (CBC vs GCM vs CTR), or corrupted encrypted data. Double-check all settings match your encryption process exactly and that the key/IV are in valid hexadecimal format.
How do I format my key and IV?
Keys and IVs should be provided in hexadecimal format. For example, a 256-bit key should be 64 hexadecimal characters (32 bytes × 2). A 16-byte IV should be 32 hexadecimal characters. Each pair of characters represents one byte. If you have binary data, convert it to hex format first.
Is my data secure when using this tool?
Yes! Everything happens right in your browser using the Web Crypto API. Your encrypted data, keys, and decrypted results never leave your computer - nothing gets uploaded to any server.
What cipher modes are supported?
We support CBC (Cipher Block Chaining), GCM (Galois/Counter Mode), and CTR (Counter Mode). Just make sure you use the same cipher mode that was used during encryption - if you encrypted with CBC, you need to decrypt with CBC.
Can I decrypt files encrypted with other tools?
Yes, as long as the encrypted data is in Base64 format and you have the key and IV. This tool works with any standard AES encryption. If your encrypted data is in binary format, you'll need to convert it to Base64 first.
Can I encrypt data with this tool?
This tool is for decryption only. We have a separate AES encryption tool for encrypting data. Both tools use the same encryption standards, so anything encrypted with our encryption tool can be decrypted here.
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