Re-enable GPG password prompt in terminal

01 Oct 2014

Problem

So I recently had cause to use GPG to encrypt something and on running the command instead of popping up a pinentry-curses window it just hung there with the following message.

You need a passphrase to unlock the secret key for
user: "Prajjwal Bhandari <[email protected]>"  
2048-bit RSA key, ID 0xBBCF9930A356E4E6, created 2014-09-04  
             (subkey on main key ID 0x438F5F1D67D55E74)

The larger problem with this, at least on my computer, is that pinentry-curses hangs waiting for access, and eating up cpu resources.

Workarounds

Don’t feed stuff through stdin

This isn’t always a solution, but if none of the other solutions work for you, this will fix it. The issue, at-least for me, only happens when something is being piped in to gpg.

Kill it with fire

The easy solution to this, and one that I had been using is

^C  
killall -9 pinentry-curses  
# Use what you would normally do to authenticate the command

Now, the problem with this is that kill -9 is ugly, but pinentry-curses won’t respond to the other signals.

Use another program

This is not an option for everyone but it is will solve the problem for most people.

First we need to find which pinentrys we have installed:

( IFS=:
for p in $PATH; do
    ls -1 $p/pinentry* 2>/dev/null
done )

Then once you’ve found them, pick one you’d like to use, say pinentry-gtk-2. Simply open $HOME/.gnupg/gpg-agent.conf in your favourite editor, and add the full path to that, like so.

pinentry-program /usr/bin/pinentry-gtk-2

Solution

Sometimes, this is not an option, maybe you’re on an ssh connection, or on a vty, or just don’t want to use anything graphical. If that is the case: add the one of the following lines, or equivalent, to your ~/.bashrc, and you are golden.

export GPG_TTY=$TTY # or GPG_TTY=`tty`

Alternatively, you can use env GPG_TTY=$TTY cmd | gpg ....

Prajjwal Bhandari