What's the difference between authorized_keys and authorized_keys2?

Just wanted a quick summary of the differences between them and why there are two?

Solution 1:

In OpenSSH prior to version 3, the sshd man page used to say:

The $HOME/.ssh/authorized_keys file lists the RSA keys that are permitted for RSA authentication in SSH protocols 1.3 and 1.5 Similarly, the $HOME/.ssh/authorized_keys2 file lists the DSA and RSA keys that are permitted for public key authentication (PubkeyAuthentication) in SSH protocol 2.0.

The release announcement for version 3 states that authorized_keys2 is deprecated and all keys should be put in the authorized_keys file.

Solution 2:

The use of authorized_keys2 for protocol 2 has been deprecated since 2001.

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Solution 3:

Originally the difference was for version differentiation.

But don't bother any more, as now the 2 can be ignored.

Solution 4:

One really good reason to use authorized_keys2 is if you have a VPS with Arvixe where the tech support team continually overwrites your authorized_keys file.