AES Encryption and Decryption

Tool Introduction

This online AES encryption and decryption tool provides a convenient and efficient way to process text or data using the Advanced Encryption Standard (AES). AES is a widely used symmetric-key encryption algorithm, known for its high strength and security, and is an industry standard for protecting data transmission and storage privacy. Whether you need to encrypt sensitive information to prevent unauthorized access or decrypt existing AES ciphertext, this tool can meet your needs. It supports multiple key lengths such as AES-128, AES-192, and AES-256, as well as various encryption modes like ECB and CBC, and supports Base64 and Hex encoding output.

AES Symmetric Encryption Principle

AES (Advanced Encryption Standard) is a block cipher algorithm that divides plaintext data into fixed-size blocks (128 bits) and then encrypts each block independently. AES is a symmetric encryption algorithm, meaning that encryption and decryption use the same key. Its core security mechanism lies in substitution and permutation operations, which transform plaintext into seemingly random ciphertext through multiple rounds of iteration.

• Key Length: AES supports three key lengths: 128-bit, 192-bit, and 256-bit. The longer the key, the harder it is to crack.
• Encryption Mode: Different encryption modes (such as ECB, CBC, CTR, etc.) process data blocks differently, affecting security, performance, and the use of Initialization Vectors (IVs).
• Initialization Vector (IV): In some encryption modes (such as CBC), an IV is a random, non-repeating value used to enhance the randomness of encryption, generating different ciphertexts even when using the same key to encrypt the same plaintext. The IV is usually transmitted with the ciphertext but does not need to be kept secret.

How to Use

1. Select Operation Type: Choose "Encrypt" or "Decrypt" according to your needs.
2. Enter Data to Process: Paste or type the plaintext you want to encrypt or the ciphertext you want to decrypt into the "Input Data" text box.
3. Enter Key: Enter the key used for encryption/decryption in the "Key" field. Please ensure that the exact same key is used for both encryption and decryption.
4. Select AES Mode: Choose the desired AES encryption mode from the dropdown menu, such as AES-128-CBC, AES-256-ECB, etc. Different modes may correspond to different key lengths.
5. Enter Initialization Vector (IV): If a mode requiring an IV (such as CBC, CTR) is selected, enter the initialization vector in the "IV" field. The length of the IV is usually the same as the AES block size (16 bytes).
6. Select Output/Input Encoding: Select the encoding format for the output result (e.g., Base64 or Hex) as needed, or specify the encoding format for the input ciphertext (when decrypting).
7. Execute Operation: Click the "Execute" button, and the tool will immediately process your data.
8. Get Results: The processing result will be displayed in the "Output Result" area, which you can copy and use.

Frequently Asked Questions

• Q: What key lengths and encryption modes does AES support?
• A: This tool supports 128-bit, 192-bit, and 256-bit key lengths. Common encryption modes include ECB, CBC, CTR, etc. Specific support is subject to the tool interface.
• Q: What are the requirements for the key and IV?
• A: The key length must match the selected AES bit length (e.g., 128-bit, 256-bit). The Initialization Vector (IV) is usually required to be 16 bytes (128 bits) long and must be consistent during encryption and decryption.
• Q: Must the key, IV, and mode be exactly the same for encryption and decryption?
• A: Yes, this is a necessary condition for successful decryption. Any inconsistency in parameters will lead to decryption failure or garbled data.
• Q: What is the difference between Base64 and Hex encoding?
• A: Base64 is an encoding method that represents binary data as ASCII strings, often used to transmit binary data in text protocols. Hex (hexadecimal) encoding is also a way to represent binary data as text, usually more concise. The choice depends on your specific needs.

Notes

• Key Confidentiality: Your key is the core of data security. Please ensure that you keep your key safe and do not disclose it to unauthorized third parties.
• Parameter Consistency: When performing encryption and decryption operations, always ensure that the key, Initialization Vector (IV), and encryption mode used are exactly the same, otherwise, correct decryption will not be possible.
• Data Encoding: For the input plaintext or ciphertext, and the output ciphertext or plaintext, please pay attention to their encoding format (e.g., UTF-8, GBK, etc.) to avoid garbled characters.
• Security: Although AES is a powerful encryption algorithm, it only provides high security when used correctly. This online tool is convenient and fast, but for extremely sensitive data or data requiring the highest level of security, it is recommended to use professional encryption software or offline tools.