mjhjmtu

SSHing into my system succeeds but even without the -v flag I get key_load_public: invalid format message. Below is the output w/ using the verbose flag.

Specifically

debug1: key_load_public: No such file or directory
debug1: identity file /home/myname/.ssh/private_rsa_key-cert type -1

seems to be the problem as I don't have such a file. However, I checked w/ another system and I also get the same two above lines. However there is no key_load_public: invalid format before that, which is what I actually want to get rid of. Permissions on the authorized_keys file on both remote systems looks the same, permissions on the private_keys look the same too.

 $ ssh -v desired_host
 OpenSSH_7.2p2, OpenSSL 1.0.2g 1 Mar 2016
 debug1: Reading configuration data /home/myname/.ssh/config
 debug1: /home/dli/.ssh/config line 16: Applying options for desired_host
 debug1: Reading configuration data /etc/ssh_config
 debug1: Connecting to desired_host [X.X.X.X] port 22.
 debug1: Connection established.
 key_load_public: invalid format
 debug1: identity file /home/myname/.ssh/private_rsa_key type -1
 debug1: key_load_public: No such file or directory
 debug1: identity file /home/myname/.ssh/private_rsa_key-cert type -1
 debug1: Enabling compatibility mode for protocol 2.0
 debug1: Local version string SSH-2.0-OpenSSH_7.2
 debug1: Remote protocol version 2.0, remote software version OpenSSH_5.3
 debug1: match: OpenSSH_5.3 pat OpenSSH_5* compat 0x0c000000
 debug1: Authenticating to desired_host:22 as 'myname'
 debug1: SSH2_MSG_KEXINIT sent
 debug1: SSH2_MSG_KEXINIT received
 debug1: kex: algorithm: diffie-hellman-group-exchange-sha256
 debug1: kex: host key algorithm: ssh-rsa
 debug1: kex: server->client cipher: aes128-ctr MAC: umac-64@openssh.com compression: none
 debug1: kex: client->server cipher: aes128-ctr MAC: umac-64@openssh.com compression: none
 debug1: SSH2_MSG_KEX_DH_GEX_REQUEST(2048<3072<8192) sent
 debug1: got SSH2_MSG_KEX_DH_GEX_GROUP
 debug1: SSH2_MSG_KEX_DH_GEX_INIT sent
 debug1: got SSH2_MSG_KEX_DH_GEX_REPLY
 debug1: Server host key: ssh-rsa SHA256:EmG/FBK0OCXtaAqAkfHKxoXKLGiZiHUsQpObK6aWd30
 debug1: Host 'desired_host' is known and matches the RSA host key.
 debug1: Found key in /home/myname/.ssh/known_hosts:39
 debug1: rekey after 4294967296 blocks
 debug1: SSH2_MSG_NEWKEYS sent
 debug1: expecting SSH2_MSG_NEWKEYS
 debug1: rekey after 4294967296 blocks
 debug1: SSH2_MSG_NEWKEYS received
 debug1: SSH2_MSG_SERVICE_ACCEPT received
 debug1: Authentications that can continue: publickey,gssapi-keyex,gssapi-with-mic,password
 debug1: Next authentication method: publickey
 debug1: Trying private key: /home/myname/.ssh/private_rsa_key
 debug1: Authentication succeeded (publickey).
 Authenticated to desired_host ([X.X.X.X]:22).
 debug1: channel 0: new [client-session]
 debug1: Requesting no-more-sessions@openssh.com
 debug1: Entering interactive session.
 debug1: pledge: network

There are two separate messages:

This one tells you that .ssh/private_rsa_key is in wrong format:

key_load_public: invalid format
debug1: identity file /home/myname/.ssh/private_rsa_key type -1

This one does not show up in without -v switch and is just informative to tell you that you don't have a certificate:

debug1: key_load_public: No such file or directory
debug1: identity file /home/myname/.ssh/private_rsa_key-cert type -1

There is nothing to worry about the second message.

I finally succeeded by being sure to copy and paste EXACTLY the contents of private RSA key, e.g.

-----BEGIN RSA PRIVATE KEY-----
<content>.....
-----END RSA PRIVATE KEY-----

including all the EOL tabs or whatever was there.

when I issued

ssh myid@mydomain

and got message (even though I successfully logged into remote box)

key_load_public: invalid format

it happened because somehow my local ~/.ssh/xxx.pub actually had contents of my private key file even though the remote host correctly had my public key in file ~myid/.ssh/authorized_keys SO solution was to correct my local ~/.ssh/xxx.pub so it had my public key