Question about signing & verifying

[ilter yÃksel <ilteryuksel@xxxxxxxxx>]

Hello,

I've question about signing especially for signing router-descriptor;

Is the router "signing-key" using to prepare a router's signature with digest algorithm? If so then does an OR sign it's router descriptor with it's signature? Finally can we say right for below sequence?

"signing-key" ---- digest algorithm --- > "router-signature"
initial "router-descriptor" ----- sign with "router-signature" --- > signed "router-descriptor"

After that how a directory authority verify whether the router descriptor is self-signed?

Thanks in advance. 
ilter