SSH Server API function to decrypt client signature

[Bruno Buzzi Brassesco <bruno.brasesco@xxxxxxxxx>]

Hi,

Implementing a SSH Server with Libssh i got two problems with the API:

It suppose that the client sends a SSH_AUTH_REQUEST to the Server and the
Server checks that:
1) The specified public key is acceptable (in the user's authorized keys)
2) Decrypting the signature with the specified public key, produces the
session identifier.
(https://tools.ietf.org/html/rfc4252#section-7)

* Which API function has to be used to get the session identifier ?
* Which API function has to be used to decrypt the signature of session
identifier ?

Unfortunately some SSH Server examples does not have a public key
authentication included:
https://github.com/substack/libssh/blob/master/examples/samplesshd.c
https://github.com/substack/libssh/blob/master/examples/samplesshd-tty.c

regards,
bruno