>>>>
AUTHORIZED*_**KEYS FILE* FORMAT
*AuthorizedKeysFile* specifies the file containing public keys for public
key authentication; if none is specified, the default is
*~/.ssh/authorized_keys*. Each line of the file contains one key (empty
lines and lines starting with a `#' are ignored as comments). Protocol
1
public keys consist of the following space-separated fields: options,
bits, exponent, modulus, comment. Protocol 2 public key consist of:
options, keytype, base64-encoded key, comment. The options field is
optional; its presence is determined by whether the line starts with a
number or not (the options field never starts with a number). The bits,
exponent, modulus, and comment fields give the RSA key for protocol
version 1; the comment field is not used for anything (but may be
convenient for the user to identify the key). For protocol version 2 the
keytype is ``ecdsa-sha2-nistp256'',
``ecdsa-sha2-nistp384'',
``ecdsa-sha2-nistp521'', ``ssh-dss'' or
``ssh-rsa''.>>>>
last line: ecdsa-sha2-nistp521 -???-> ecdsa-sha2-nistp512
Tev