SSH with asymmetric key UML Sequence

dh-diagram.svg

diagram.plantuml

@startuml
participant Client as C
participant Server as S


Title SSH Asymmetric Internals Sequence
== Initial Connection ==

C --> S: Connection establishment request
S --> C: Here are the protocols I support & my public host-key (identifier)                            
C --> C: Do I support these methods? (If None Supported Fail)

== Diffie-Hellman ==

C <-> S: Agree publicly on `prime modulus`(PM) & `generator`(G) 
C --> C: Generate private random number (PRNI)
C --> C: Generate public random number (PRNS) = G<sup>PRNI</sup>%PM)
C --> S: sends PRNS
S --> S: Generate private random number (PRNI)
S --> S: Generate public random number (PRNS) = G<sup>PRNI</sup>%PM)
S --> C: sends PRNS
C --> C: Use Server PRNS<sup>PRNI</sup>%PM to generate shared secret (SS)
S --> S: Use Client PRNS<sup>PRNI</sup>%PM to generate shared secret (SS)

== Authentication (asymmetric key) ==

C --> S: Transmit identity seeking to prove
S --> S: Verify account being accessed contains identity supplied
...If identity Not Found Fail...
S --> S: Generate new private random number (PRNC)
S --> S: Encrypt PRNC (PRNCE) with the public-key found
S --> C: Send Client PRNCE
C --> C: Attempt to decrypt PRNCE using private-key matching sent identity
C --> S: Send Hash of the SS & decrypted PRNCE (VHASH)
S --> S: Generates hash & compares hash to VHASH
...If Not Matching Fail...

@enduml