Encrypt string using PCLCrypto

Question

I have a RSA key which I got from a service provider. I just want to encrypt the string data with that RSA key by using the PCLCrypto library. I don't want to create the RSA key by using PCLCrypto. I only wanted to encrypt the data. (I am developing a PCL component in xamarin.)

Answer 1

Follow the documentation for AES encryption and modify it for RSA. Use AsymmetricAlgorithm.RsaPkcs1 as algorithm provider.

Below example is for AES.

byte[] keyMaterial;
byte[] data;
var provider = WinRTCrypto.SymmetricKeyAlgorithmProvider.OpenAlgorithm(SymmetricAlgorithm.AesCbcPkcs7);
var key = provider.CreateSymmetricKey(keyMaterial);

// The IV may be null, but supplying a random IV increases security.
// The IV is not a secret like the key is.
// You can transmit the IV (w/o encryption) alongside the ciphertext.
var iv = WinRTCrypto.CryptographicBuffer.GenerateRandom(provider.BlockLength);

byte[] cipherText = WinRTCrypto.CryptographicEngine.Encrypt(key, data, iv);

// When decrypting, use the same IV that was passed to encrypt.
byte[] plainText = WinRTCrypto.CryptographicEngine.Decrypt(key, cipherText, iv);