public void Decrypt()
{
var encryptedKeyXml = GetEncryptedKey();
var encryptedKey = new EncryptedKey();
encryptedKey.LoadXml(encryptedKeyXml);
byte[] symmetricKey = RsaOaepSha256.Decrypt(encryptedKey.CipherData.CipherValue, Certificate);
var symmetricAlgorithm = new AesGcm {
Key = symmetricKey
};
foreach (var attachment in Attachments)
{
attachment.Stream.Position = 0;
var nonce = new byte[AesGcm.NonceSize / 8];
attachment.Stream.Read(nonce, 0, nonce.Length);
symmetricAlgorithm.Nonce = nonce;
var decryptedStream = new MemoryStream();
var cryptoStream = new CryptoStream(attachment.Stream, symmetricAlgorithm.CreateDecryptor(), CryptoStreamMode.Read);
cryptoStream.CopyTo(decryptedStream);
if (!cryptoStream.HasFlushedFinalBlock)
{
cryptoStream.FlushFinalBlock();
}
attachment.Stream = decryptedStream;
}
}