PGP Encrypt from C # using GnuPG

Question

I am trying to encrypt an incoming document in C # and I am using GnuPG with input redirection. I need to use -se (sign and encrypt) in one step, which requires a passphrase. But for some reason input redirection does not work. I appreciate your help. Control will block. I'm not sure that pending input will be deadlock or child process (gpg.exe).

pgpproc = new Process();
pgpproc.StartInfo.FileName = exeFilePath;
pgpproc.StartInfo.RedirectStandardOutput = false;
pgpproc.StartInfo.RedirectStandardInput = true;
pgpproc.StartInfo.UseShellExecute = false;
pgpproc.StartInfo.Arguments = "-a  -o C:\PGPStaging\output.pgp -se -r recipientID C:\PGPStaging\input.txt";
pgpproc.StartInfo.CreateNoWindow = true;
pgpproc.Start();
StreamWriter myStreamWriter = pgpproc.StandardInput;
myStreamWriter.Write("*****");
myStreamWriter.Close();

if (pgpproc.WaitForExit(waittime))
{
  //success
}
else
{
  //failure
  pgpproc.Kill();
  pgpproc.WaitForExit();
}

`

Answer 1

, , , , / gnupg. (\n 0x13 0x130x10, ) . -, Enter, , . , OpenPGPBlackbox .

Answer 2

--passphrase-fd 0 GnuPG, .

Answer 3

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    procStartInfo.Arguments = @"/c echo " + passphrase + @"| c:\gnupg\gpg --passphrase-fd --     decrypt --output " + "\"" + fileLocationToDecryptTo + "\"" + " \"" + fileLocationToDecryptFrom     + "\"";

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