/// <summary>Encrypt text using a public key</summary>
public static string Encrypt(string plainText, RSAKeyValues key)
{
// validate input
if (!IsKeySizeValid((int)key.KeySize))
{
throw new ArgumentException("Key size is not valid", "keySize");
}
if (String.IsNullOrEmpty(plainText))
{
throw new ArgumentException("Nothing to encrypt", "plainText");
}
int maxLength = GetMaxDataLength((int)key.KeySize);
byte[] data = Encoding.UTF8.GetBytes(plainText);
if (data.Length > maxLength)
{
throw new ArgumentException($"Maximum data length is {maxLength}.", "data");
}
using var provider = new RSACryptoServiceProvider((int)key.KeySize);
provider.ImportParameters(key.Parameters);
byte[] encdata = provider.Encrypt(data, OptimalAsymmetricEncryptionPadding);
return(Convert.ToBase64String(encdata));
}
/// <summary>Decrypt using the private key</summary>
public static string Decrypt(string encryptedText, RSAKeyValues key)
{
// validate input
if (!IsKeySizeValid((int)key.KeySize))
{
throw new ArgumentException("Key size is not valid", "keySize");
}
byte[] encdata = Convert.FromBase64String(encryptedText);
using var provider = new RSACryptoServiceProvider((int)key.KeySize);
provider.ImportParameters(key.Parameters);
byte[] data = provider.Decrypt(encdata, OptimalAsymmetricEncryptionPadding);
return(Encoding.UTF8.GetString(data));
}
/// <summary>Signs some data with the specified private asym key using SHA-256</summary>
/// <param name="data"></param>
/// <returns></returns>
public static byte[] SignWithSHA256(byte[] data, RSAKeyValues key)
{
if (data == null || data.Length < 1)
{
throw new ArgumentException("Nothing to sign.", "data");
}
// validate input
if (!IsKeySizeValid((int)key.KeySize))
{
throw new ArgumentException("Key size is not valid", "keySize");
}
using var provider = new RSACryptoServiceProvider((int)key.KeySize);
provider.ImportParameters(key.Parameters);
byte[] sig = provider.SignData(data, HashAlgorithmName.SHA256, RSASignaturePadding.Pkcs1);
return(sig);
}