Decode & Inspect Certificate Signing Requests CSR Decoder tool for network operations.

The tool works by first validating the input PEM-encoded CSR to ensure it starts with the expected header, either '-----BEGIN CERTIFICATE REQUEST-----' or '-----BEGIN NEW CERTIFICATE REQUEST-----'. If valid, it trims and cleans the input string, removing any unnecessary characters. It then uses the `atob` function to decode the base64-encoded data into a binary string, which is subsequently converted into a Uint8Array for easier manipulation. The tool extracts human-readable strings from this binary data using the `TextDecoder` API, specifically looking for strings that match certain patterns such as country codes or common names.

The extracted text parts are then mapped to their corresponding OID labels, such as 'Country (C)', 'Common Name (CN)', or 'Organization (O)', based on predefined rules and regular expressions. The resulting information is stored in a Record object, which contains key-value pairs for each extracted field. If multiple text parts are found, they are concatenated into a single string under the 'All Extracted Fields' key. The tool uses React hooks, specifically `useState` and `useCallback`, to manage its state and handle user interactions, such as decoding the CSR or copying the result as JSON.

The use of ES6+ features like destructuring and arrow functions contributes to the tool's conciseness and readability. Additionally, the mobile-first responsive design ensures that the tool is accessible and usable across various devices and screen sizes. The `copyToClipboard` function from the `@/lib/utils` module is used to copy the result as JSON, allowing users to easily integrate the extracted information into other workflows or tools. By leveraging modern JavaScript APIs and following established standards and RFCs, the tool provides a reliable and efficient way to decode and extract information from CSRs in the browser.