/// <summary>
/// Decrypt a stream
/// </summary>
/// <param name="encrypt"></param>
/// <param name="inputStream">readable stream with encrypted data</param>
/// <param name="outputStream">writable stream for decrypted data</param>
/// <param name="bufferSize"></param>
/// <exception cref="ArgumentException"></exception>
public static void DecryptStream(this EasyEncrypt encrypt, Stream inputStream, Stream outputStream,
int bufferSize = DefaultBufferSize)
{
if (encrypt == null)
{
throw new ArgumentException("Can't encrypt data: encrypt class is null");
}
if (inputStream == null || !inputStream.CanRead)
{
throw new ArgumentException("Can't encrypt data: inputStream is not readable");
}
if (outputStream == null || !outputStream.CanWrite)
{
throw new ArgumentException("Can't encrypt data: output stream is not writable");
}
byte[] iv = new byte[encrypt.Algorithm.IV.Length];
inputStream.Read(iv, 0, iv.Length);
encrypt.Algorithm.IV = iv;
using var decrypter = encrypt.Algorithm.CreateDecryptor(encrypt.Algorithm.Key, encrypt.Algorithm.IV);
using var cs = new CryptoStream(inputStream, decrypter, CryptoStreamMode.Read);
var buffer = new byte[bufferSize];
int read;
while ((read = cs.Read(buffer, 0, buffer.Length)) > 0)
{
outputStream.Write(buffer, 0, read);
}
}
/// <summary>
/// Decrypt a file
/// </summary>
/// <param name="encrypt">encrypted input file</param>
/// <param name="fileIn">location of new decrypted file</param>
/// <param name="fileOut"></param>
/// <param name="bufferSize"></param>
public static void DecryptFile(this EasyEncrypt encrypt, string fileIn, string fileOut,
int bufferSize = DefaultBufferSize)
{
using var fileInStream = new FileStream(fileIn, FileMode.Open);
using var fileOutStream = new FileStream(fileOut, FileMode.Create);
encrypt?.DecryptStream(fileInStream, fileOutStream, bufferSize);
}
