Encrypt or Decrypt with Blowfish Cipher Online Encrypt and decrypt text using the Blowfish cipher.

The tool works by utilizing the CryptoJS library, specifically its implementation of the Blowfish cipher, which is a symmetric-key block cipher that operates on 64-bit blocks using a variable-length key. Under the hood, it employs a 16-round Feistel structure, where each round consists of four key-dependent S-boxes and an 18-entry P-array. The key setup involves 521 encryption iterations to derive the subkeys used in the encryption process. When encrypting or decrypting data, the tool uses the EVP_BytesToKey method provided by CryptoJS to convert the user-provided secret key into a format suitable for the Blowfish algorithm.

In terms of browser APIs and data structures, the tool relies on React state management using hooks such as useState and useCallback to store and update the input text, secret key, mode, and output. The process function is where the actual encryption or decryption occurs, and it uses CryptoJS's Blowfish.encrypt or Blowfish.decrypt methods to perform the necessary operations. The encrypted or decrypted data is then stored in the output state variable and displayed to the user in a textarea element.

When dealing with errors, the tool catches any exceptions that occur during the encryption or decryption process and displays an error message to the user indicating what went wrong, such as providing both input and key, checking the key and ciphertext for decryption failures, or general encryption or decryption failure due to invalid inputs. Additionally, it uses a copy-to-clipboard function implemented using the copyToClipboard utility from the @/lib/utils module, allowing users to easily share their encrypted or decrypted text.

The tool's use of 64-bit blocks makes it vulnerable to birthday attacks, which can be mitigated by using larger block sizes or more secure cryptographic algorithms. However, for its intended purpose as a simple online Blowfish encryption and decryption tool, the current implementation provides an effective and easy-to-use solution for testing and demonstrating the Blowfish algorithm. The specific technologies used in this implementation include React for building the user interface, CryptoJS for handling the underlying cryptography, and TypeScript for ensuring type safety throughout the codebase.

The data formats involved in the encryption and decryption process are primarily strings, which represent the input text, secret key, and output ciphertext or plaintext. When decrypting data, the tool uses the CryptoJS.enc.Utf8 encoding scheme to convert the decrypted bytes back into a human-readable string. This ensures that the output is correctly formatted and easily readable by users. Overall, the combination of these technologies and techniques allows the tool to provide a straightforward and user-friendly interface for performing Blowfish encryption and decryption operations online.