protected AesCryptoServiceBase(AesCspParameters aesCspParameters)
{
if (null == aesCspParameters)
{
throw new ArgumentNullException(nameof(aesCspParameters));
}
aes = new AesCryptoServiceProvider {
Key = HexTk.UnHex(aesCspParameters.AesKey),
IV = HexTk.UnHex(aesCspParameters.AesIv)
};
}
/// <summary>
/// inverts the encryption of a string - works if the same AES key has been used for encryption.
/// Notice for programmers: Each decryption needs a fresh decryptor, reuse of decryptor throws ugly exceptions.
/// </summary>
/// <param name="encryptedText"></param>
/// <returns></returns>
protected string DecryptString(string encryptedText)
{
var decrypted = string.Empty;
try {
var trimmed = encryptedText.ParseText();
if (!string.IsNullOrEmpty(trimmed))
{
var unHexed = HexTk.UnHex(trimmed);
using var msDecrypt = new MemoryStream(unHexed);
// must get a fresh Decryptor for each decryption
var decryptor = aes.CreateDecryptor();
using var csDecrypt = new CryptoStream(msDecrypt, decryptor, CryptoStreamMode.Read);
using var srDecrypt = new StreamReader(csDecrypt);
decrypted = srDecrypt.ReadToEnd();
}
} catch (Exception exception) {
Log.Warning(exception, AesResources.Decryption_Failed, encryptedText);
}
return(decrypted);
}