AES Encrypt / Decrypt Encrypt and decrypt text using AES with a passphrase.

The tool works under the hood by utilizing the CryptoJS library to handle AES encryption and decryption operations. When a user initiates an operation, it first checks if both input and key are provided, then proceeds with either encrypting or decrypting the data using the AES-256-CBC algorithm from CryptoJS. The EVP_BytesToKey method is used for deriving a 256-bit key and initialization vector (IV) from the given passphrase, ensuring unique encryption results even when using the same key. This process involves generating random salts and applying PKCS7 padding to ensure secure data transmission.

In terms of implementation details, it uses React state management with hooks like useState and useCallback to efficiently handle user interactions and update the output accordingly. The CryptoJS library provides functions for AES encryption and decryption, which are then wrapped in a try-catch block to catch any potential errors during execution. Upon successful operation completion, the resulting ciphertext or decrypted text is displayed in a read-only textarea, allowing users to easily copy the output using the built-in copy-to-clipboard function provided by the copyToClipboard utility from the '@/lib/utils' module.

When handling encryption operations, CryptoJS generates a random 8-byte salt and derives a key via EVP_BytesToKey. The resulting ciphertext is formatted as "Salted__" followed by the salt and actual encrypted data, all of which are Base64-encoded to facilitate easy sharing or storage. This specific output format ensures that both the encryption key and initialization vector can be securely stored along with the ciphertext itself, enabling correct decryption later on using the same passphrase. During decryption operations, CryptoJS uses this stored information to correctly derive the necessary keys for decrypting the provided AES-256-CBC encrypted data back into its original plaintext form.

The tool's client-side implementation relies heavily on browser APIs and built-in JavaScript functionality, ensuring that all encryption and decryption processes occur locally within the user's web browser. This approach eliminates potential security risks associated with transmitting sensitive information over a network connection, making it suitable for protecting confidential data online. By combining React state management, CryptoJS library functions, and carefully designed output formatting, this tool provides an efficient solution for securely encrypting text online using AES-256 encryption with passphrase key derivation in the browser itself.