Encrypt and Decrypt with RSA Keys in Your Browser Encrypt and decrypt using RSA public-key cryptography.

The tool uses the RSA-OAEP protocol to perform encryption and decryption operations, relying on the Web Crypto API for cryptographic functions. Under the hood, it utilizes the `window.crypto.subtle` interface to import keys in PEM format and execute encryption and decryption processes. The key importing process involves converting the PEM string to an ArrayBuffer using base64 decoding and then passing it to the `importKey` method. For encryption, the tool uses the `RSA-OAEP` algorithm with a hash function of `SHA-256`, while for decryption, it employs the same algorithm but imports the private key in PKCS#8 format.

When processing input data, the tool encodes plain text into a Uint8Array using the `TextEncoder` API and then passes it to the `encrypt` method. The encrypted result is then converted to a base64-encoded string using the `btoa` function. Conversely, when decrypting ciphertext, the tool converts the base64 input string back to a Uint8Array and then uses the `decrypt` method to obtain the original plain text. Error handling is also implemented, catching any exceptions that occur during the encryption or decryption process and displaying an error message to the user.

The RSA-OAEP protocol itself adds randomized padding to the input data using the MGF1 mask generation function and SHA-256 hashing, ensuring IND-CCA2 security. The maximum plaintext size that can be encrypted is determined by the key length minus twice the hash length minus two, which for a 2048-bit key with SHA-256 hashing works out to around 190 bytes. By using the Web Crypto API and following established cryptographic protocols, the tool provides a secure and reliable means of performing RSA encryption and decryption operations directly in the browser. The use of specific technologies like React and TypeScript also ensures that the tool is maintainable and efficient.