Instant messaging client and server

The invention provides an instant messaging client and server. The client comprises a finger printing initiating unit, a finger printing receiving unit, a position uploading unit, a position display unit and a position processing unit, wherein the finger printing initiating unit can provide a finger printing interface in a session message interface after receiving a finger printing starting instruction initiated by a user and initiate a finger printing request to a finger printing opposite user after receiving a pressing gesture of the user; the finger printing receiving unit outputs a finger printing responding interface after receiving a finger printing request initiated by the finger printing opposite user and upload the pressing position received by the fingerprint printing interface to the server; the position display unit is used for receiving the pressing position of the finger printing opposite user, which is issued by the server, and displaying the pressing position of the finger printing opposite user inside a local finger printing interface; the finger printing unit is used for outputting finger printing success prompt information to the local user after receiving a finger printing success message, which is transmitted by the server when the pressing position is matched.