Create SSH Key Pairs in Your Browser Generate RSA and ECDSA key pairs for SSH authentication.

The tool uses the Web Crypto API to generate secure ssh key pairs directly in the browser. Specifically, it utilizes the `crypto.subtle.generateKey()` method to create RSA and ECDSA keys. For RSA, it employs the RSASSA-PKCS1-v1_5 algorithm with a SHA-256 hash function, while for ECDSA, it uses the P-256 curve. The generated keys are then exported in SPKI (Subject Public Key Information) format for public keys and PKCS#8 format for private keys using `crypto.subtle.exportKey()`. This process ensures that private keys remain secure and never leave the user's browser.

Under the hood, the tool relies on React state management to handle key generation and storage. It uses `useState` hooks to maintain the current key type, size, and generated public and private keys. The `useCallback` hook is used to memoize functions that generate keys and copy them to the clipboard. When generating keys, it converts the resulting ArrayBuffer to a base64-encoded string using the `ab2b64()` function, which is then formatted into PEM (Privacy-Enhanced Mail) format using the `fmtPem()` function.

The tool's key generation process involves creating an instance of the Web Crypto API's `generateKey` method, passing in the desired algorithm and key size. For RSA keys, this includes specifying a modulus length of 2048 or 4096 bits, as well as a public exponent of 65537 (0x10001). The resulting key pair is then exported using the `exportKey` method, which returns an ArrayBuffer containing the encoded key data. This data is subsequently converted to PEM format and displayed in a textarea for easy copying.

In terms of security, the tool's use of the Web Crypto API ensures that all key generation and storage occurs within the browser, minimizing the risk of private key exposure. The generated keys are also formatted according to standard PEM conventions, making it easy to integrate them with existing systems that rely on this format. By leveraging established cryptographic algorithms like RSASSA-PKCS1-v1_5 and ECDSA, the tool provides a secure means of generating ssh key pairs for authentication purposes.

The `fmtPem()` function plays a crucial role in formatting the generated keys into PEM format. It takes two arguments: the base64-encoded key data and the type of key being formatted (either "PUBLIC KEY" or "EC PRIVATE KEY"). The function splits the key data into 64-character chunks, joining them with newline characters to create the final PEM-formatted string. This formatting is essential for ensuring compatibility with existing systems that rely on PEM-encoded keys.

The tool's clipboard functionality is handled by the `copyToClipboard()` function, which takes a string argument representing the text to be copied. It uses the browser's built-in `navigator.clipboard` API to write the provided text to the system clipboard. The function returns a boolean value indicating whether the copy operation was successful, allowing the tool to display a confirmation message or error notification as needed.

The React library is used extensively throughout the tool, providing a framework for building and managing the user interface. Specifically, it uses React's `useState` hook to maintain state variables like key type, size, and generated keys. The `useCallback` hook is also employed to memoize functions that handle key generation and clipboard operations.

The use of specific technologies like Web Crypto API, React, and PEM formatting enables the tool to provide a secure means of generating ssh key pairs directly in the browser. By leveraging these established standards and libraries, it simplifies the process of managing access to systems while minimizing security risks associated with private key exposure.