Cannot ssh to server even though rsa_id.pub has been inserted to authorized keys

Question

I can ssh to a server using my windows machine. There, I put the ssh key of my Linux machine (~/.ssh/id_rsa.pub) into the ~/.ssh/authorized_keys file. However, I cannot ssh to the server using my Linux machine:

$ ssh xyz@172.16.0.32


sign_and_send_pubkey: signing failed for RSA "/home/xyz/.ssh/id_rsa" from agent: agent refused operation
xyz@172.16.0.32: Permission denied (publickey).

What could I be doing wrong?

Edit:

I just applied

chmod 700 ~/.ssh
chmod 600 ~/.ssh/authorized_keys

which did not have an effect on the issue.

Answer 1

I had to change the permissions of id_rsa and id_rsa.pub:

chmod 700 id_rsa*

Answer 2

The right permissions are

chmod 600 id_rsa         # rw-------
chmod 644 id_rsa.pub     # rw-r--r--

or using symbolic permissions:

chmod u=rw,go=  id_rsa
chmod u=rw,go=r id_rsa.pub

The .pub file is the public key, and it can be readable by anyone. It's only the private key which must have permissions restricted to the owner.