After randomly genetating a and b$,$ output $($A$,$ gA$($mod p$))$ and $($B$,$ gB$($mod p$))$ and the secret key gAB

$($mod p$)$ established between your VPC $($named by your first name$)$ and your data centre $($named by

your surname$)$ by the Diffie$-$Hellman key exchange protocol, where A$=$SHA$1($a$,$ your first name$)$ and

B$=$SHA$1($b$,$ your surname$)$