# How to use gpg as ssh agent.

If you don’t know how to create GPG keys read [How to create GPG key-pair](https://dev.vengalath.com/how-to-create-gpg-keypair)

This setup is for Mac users

Enable the GPG-agent ssh support by typing this in your terminal


```
echo enable-ssh-support >> $HOME/.gnupg/gpg-agent.conf
``` 

Set SSH_AUTH_SOCK so that SSH will use GPG-agent instead of ssh-agent. Add this to to your .bashprofile or .zshrc

To know your SHELL type 


```
echo $SHELL
``` 

this will print /bin/zsh or /bin/bash

open the .zshrc file by typing


```
cd && nano .zshrc
``` 

or open .bashprofile by typing 


```
cd && nano .bash_profile
``` 



Add the following to the file (.bashprofile or .zshrc)

```
unset SSH_AGENT_PID
if [ "${gnupg_SSH_AUTH_SOCK_by:-0}" -ne $$ ]; then
  export SSH_AUTH_SOCK="$(gpgconf --list-dirs agent-ssh-socket)"
fi
export GPG_TTY=$(tty)
gpg-connect-agent updatestartuptty /bye >/dev/null
``` 

Enable the gpg subkey for ssh authentication

Type the following command to get the the sub-key key grip


```
gpg --list-keys --with-keygrip
``` 

This may print the following 


```
amrith@V ~ % gpg -K --with-keygrip
/Users/amrith/.gnupg/pubring.kbx
--------------------------------
sec#  rsa4096 2021-02-07 [SC] [expires: 2031-02-07]
      10B0C3E9867BC44CDA48690C8678CFE303EBDB52
      Keygrip = CD02E01C898C378214163C91F3D1E93107B0EBDB
uid           [ultimate] Amrith Vengalath 
ssb   rsa4096 2021-02-07 [E] [expires: 2023-02-09]
      Keygrip = 4778AA4AE919B0387C24389FC2E86C4B7749FAD4
ssb   rsa4096 2021-02-09 [S] [expires: 2023-02-09]
      Keygrip = B19D2224DBBBCC324679AC3CDA97337035477338
ssb   rsa4096 2021-02-10 [A] [expires: 2023-02-10]
      Keygrip = 53C518FCC568C4D3659AD3FF0C0A567CC9593DB5
``` 

Add the keygrip of your subkey in the list of approved keys by the following command


```
echo 53C518FCC568C4D3659AD3FF0C0A567CC9593DB5 >> ~/.gnupg/sshcontrol
``` 

I typed ```53C518FCC568C4D3659AD3FF0C0A567CC9593DB5``` here since that is my keygrip replace this with yours

Now type the following command to check if the key is present in the ssh identities list


```
ssh-add -l
``` 
output

```
4096 SHA256:adp8owth5AD41Hk6uHYY3M5rl/GJNzizQIXwRugS5t0 (none) (RSA)
``` 

Retrieve the public ssh key for the subkey

for that type the following command
```
gpg --export-ssh-key 03EBDB52
``` 
output

```
ssh-rsa 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 openpgp:0x4893D8CE
``` 
You can test if the key is working with your Github account. The ssh public key generated in the previous step has to be added to your Github SSH keys.


```
ssh -T git@github.com
``` 
output

```
Hi AmrithVengalath! You've successfully authenticated, but GitHub does not provide shell access.
```