Permission denied (publickey).


Many equations and formulas look intimidating. However, when you hunt them down, they are definitely not! Just papertigers!

Now let's hunt the papertiger.

A problem occurred while I `git push` to my git server on ec2.

I handled this by following this three guide of which their original links are:

Sorry for missing out the second source link, I will add that later.

Firstly, check your url if it’s right. If it’s outdated, update it with:

git remote set-url origin git://


sign_and_send_pubkey: signing failed: agent refused operation
Permission denied (publickey).
fatal: Could not read from remote repository.

  1. mkdir ~/.ssh
  2. vim known_hosts – if you already have known_hosts, skip this.
  3. ssh-keyscan -t rsa >> ~/.ssh/known_hosts
  4. ssh-keygen -t rsa -C ""
  5. Add the key to SSH keys list on your GitHub profile.

Set up your client

  1. Generate your key
    • ssh-keygen
  2. Configure ssh to use the key
    • vim ~/.ssh/config
  3. Copy your key to your server
    • ssh-copy-id -i /path/to/ SERVERNAME

Your config file from step 2 should have something similar to the following:

Hostname ip-or-domain-of-server
PubKeyAuthentication yes
IdentityFile ./path/to/key

eval “$(ssh-agent -s)”


There are many excellent tutorials out there. Some tutorials are too intuitive and it's helpful, but you cannot get it straight on the math details. Some focused on dymestifying math. Some focused on code. I found the best tutorials that give you the conceptual ideas and are possible for implementation without being blind to the math details. Drop a comment if I failed. It would be really appreciable.

If you want to cite this article, please cite this article as:

Lachlan Chen, "Permission denied (publickey).," in EarnFromScratch, 三月 21, 2017,


title=Permission denied (publickey).,
author={Chen, Lachlan},
year=三月 21, 2017

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