AES Text Decryption Tool

Decrypt text that was encrypted using AES (Advanced Encryption Standard) algorithm. This tool supports AES-128, AES-192 and AES-256 decryption modes.

Encrypted Text (Base64 encoded):

Decryption Key:

Initialization Vector (IV - Base64 encoded, optional for some modes):

AES Mode:

Key Size:

Decryption Result:

About AES Decryption

The Advanced Encryption Standard (AES) is a symmetric encryption algorithm widely used across the globe to secure sensitive data. This tool allows you to decrypt text that was encrypted using AES algorithms.

How to Use This Tool

Paste your AES-encrypted text (in Base64 format) into the first field
Enter the secret key that was used for encryption
If an Initialization Vector (IV) was used during encryption, enter it (also in Base64 format)
Select the AES mode and key size that matches your encryption settings
Click "Decrypt Text" to see the original message

AES Modes Explained

CBC (Cipher Block Chaining): Each block of plaintext is XORed with the previous ciphertext block before being encrypted. Requires an IV.
GCM (Galois/Counter Mode): Provides both confidentiality and authenticity. Requires an IV (often called nonce in this mode).
CFB (Cipher Feedback): Turns the block cipher into a stream cipher. Requires an IV.
OFB (Output Feedback): Also turns the block cipher into a stream cipher. Requires an IV.
ECB (Electronic Codebook): The simplest mode where each block is encrypted independently. Not recommended for most uses as it reveals patterns in the plaintext.

Security Information

This tool performs all decryption in your browser using JavaScript. Your encrypted data and secret key are never sent to our servers, ensuring maximum privacy and security.

Frequently Asked Questions

What is AES encryption?

AES (Advanced Encryption Standard) is a symmetric block cipher chosen by the U.S. government to protect classified information and is implemented in software and hardware throughout the world to encrypt sensitive data.

What key sizes does AES support?

AES supports three key lengths: 128 bits, 192 bits, and 256 bits. AES-256 provides the strongest encryption but requires more computational resources.

Why is ECB mode not recommended?

ECB mode encrypts identical plaintext blocks into identical ciphertext blocks, which can reveal patterns in the data. More secure modes like CBC or GCM should be used instead.

What is an Initialization Vector (IV)?

An IV is a random value used with the encryption key to ensure that the same plaintext encrypted multiple times will produce different ciphertexts each time, enhancing security.

Is this tool secure to use?

Yes, all decryption happens in your browser. Your encrypted data and secret key never leave your computer and are not transmitted over the internet.