A machine-readable code is generated in response to a request from a first user. The request specifies a number of times or a time period during which the machine-readable code can be validly scanned electronically. The machine-readable code is displayed on a device of the first user. The machine-readable code is electronically scanned by a device of a second user. A determination is made as to whether a scan of the machine-readable code by the device of the second user occurred within the specified number of times or within the specified time period. An electronic interaction between the first user and the second user is performed response to the determination, while an identity of the first user or an identity of the second user is concealed from each other and from social media contacts of the first user and the second user.