A server apparatus is operable in communication with mobile client apparatuses for securely recording the occurrence of a transactional exchange meeting between holders of the mobile client apparatuses. A token component sets up a meeting arrangement mediated by the server and to communicate a first issued token to a first mobile client apparatus and a second issued token to a second mobile client apparatus. A token validator component receives at least a portion of each of the tokens from the mobile client apparatuses. The token validator component validates that the at least a portion of the token received from the first mobile client apparatus matches at least a portion of the second issued token, and vice-versa. A transaction recorder component creates and maintains a secure record of at least the request, the response, the validation of the tokens, and a completion signal from each of the mobile client apparatuses.