Is it possible to encrypt file symmetrically with 1
(one) command line?
amilivojevic at pbl.ca
Fri Oct 1 16:40:31 CEST 2004
Chris De Young wrote:
> On Thu, Sep 30, 2004 at 11:25:33PM +0200, Oleksiy Muzalyev wrote:
>>I call from VB2005:
>>Shell("c:\gnupg\gpg.exe -a -c " & fileToEncrypt, AppWinStyle.NormalFocus)
>>And console window opens and asks twice for the password.
>>I would prefer to send the file path and password in one command.
> Offhand I don't know of any switches that you can use to pass the
> passphrase on the command line, though I might be missing one. If
> it's acceptable to store the passphrase in a separate file (probably
> no more risky that coding it into a script), you could use:
> gpg -a -c --batch --passphrase-fd n filename
> which will read the password from file descriptor n. 0 means standard
> input, though that's not what you want in the case.
Hm, why not using 0? I don't know how VB handles redirection of
stdin/stdout between processes, however this works quite well in Perl on
$gpg_exe = "gpg";
@gpg_args = ($gpg_exe, "--quiet", "--batch", "--no-tty",
"--passphrase-fd", "0", "-a", "-c", "blah");
open(FH, "|-") || exec @gpg_args or die "Can't execute GnuPG!";
print FH "passpharase\n";
close(FH) or die "Encryption failed!";
What this does is that it starts new gpg process, and ties its standard
input to file handle of parent process (basically it creates a pipe
between two processes). Then it sends the passpharase using this pipe.
Note the newline at the end of passphrase. If this can be ported to
VB on Windows, it *should* work (tm).
To prevent this going into the wrong direction, yes I do know that
having passphrase in code is insecure, and yes I do know there are
couple of nice Perl modules for handling GnuPG, and yes I do know this
is not the best way of controlling GnuPG from another process. This was
just illustration, and for simple usage and with few precausions it works.
Aleksandar Milivojevic <amilivojevic at pbl.ca> Pollard Banknote Limited
Systems Administrator 1499 Buffalo Place
Tel: (204) 474-2323 ext 276 Winnipeg, MB R3T 1L7
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