gpg-agent protocol

Dubravszky József mail at
Fri Dec 4 14:43:52 CET 2015


Thank you Yutaka San. That was my first idea but have not got the chance to
try it. But most certainly I will try it the current shared memory
operations based protocol.
On #gnupg @ Freenode <aheinecke> had this idea, that gpg-agent.exe uses
Windows named pipes and it could be used with gpg-connect-agent -S
C:\Users\USERNAME\AppData\Roaming\gnupg\S.gpg-agent.ssh. If the shmop
version fails, will give this a shot too.
Anyways, I will post results.



Dubravszky József
mail at
+36 30 435 7816

-----Original Message-----
From: NIIBE Yutaka [mailto:gniibe at] 
Sent: Thursday, December 03, 2015 1:47 AM
To: gnupg-devel at
Subject: Re: gpg-agent protocol

On 12/03/2015 12:17 AM, Dubravszky József wrote:
> Atsuhiko Yamanaka made an excellent Eclipse SSH agent plugin
> ( to proxy SSH agents to Eclipse
> subsystems. Currently it supports ssh-agent on Linux and Pageant on

It's good to hear his name again.  Great.

I guess it also just works with gpg-agent, possibly.  (Newer)
gpg-agent supports the communication method of Pageant<->Putty.

> My question might sound silly, but is there anything that would
> prevent me writing a connector that uses the same Win32 shared
> memory operations based protocol?

IIUC, the connector for Pageant works with gpg-agent, because it's the
same protocol.  Please try.

> I also recognized that on Windows an S.gpg-agent.ssh file is created in
> users roaming AppData
> (C:\Users\USERNAME\AppData\Roaming\gnupg\S.gpg-agent.ssh), that pretty
> resembles a Unix socket. As far as I know there is no such compatible
> socket on Windows, but what is this file then?

Please note that my knowledge is limited since I'm not a Windows user.
GnuPG implements Unix domain socket emulation and use it for
gpg<->gpg-agent communication.  The S.gpg-agent.ssh is the one for
SSH, while there are no client program on Windows (Putty uses another
channel: Win32 shared memory operations).

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