Question about key file formats used by OpenSSH

[Elvis Stansvik]

2009/2/2, Elvis Stansvik <elvstone at gmail.com>:
> Hello OpenSSH developers, first post.
>
> I'm implementing SSH agent functionality in a program of mine, with
> the ability to add/remove keys files as saved by OpenSSH. So I'm
> trying to figure out which formats OpenSSH uses natively for the
> different types of keys. The only specification related to SSH key
> file formats I've found is RFC4716 (SSH Public Key File Format).
>
> Analysis of ssh-keygen output with varying key types shows the
> following four formats for which I haven't found any specification:
>
>  * Something similar to RFC4716 and RFC1421, but not quite the same.
>     Used by OpenSSH for version 2 DSA and RSA private keys.
>
>  * "ssh-dss|rsa-dss [base64?] comment".
>     Used by OpenSSH for version 2 DSA and RSA public keys.
>
>  * "[keysize?] [decimal number] [more decimal numbers]".
>     Used by OpenSSH for version 1 RSA public keys.

Sorry. Should be "[keysize?] [decimal number] [more decimal numbers] [comment]".

Elvis

>
>   * ASCII header line followed by binary data.
>     Used by OpenSSH for version 1 RSA private keys.
>
> Are these formats specified somewhere, short of reading OpenSSH source
> code? Why not use RFC4716 natively?
>
> Best regards,
> Elvis Stansvik
>