Package-receiving-lockers (PRLs) may have a collapsible-locker portion and door-attachment-structure. PRLs may exist in a substantially collapsed configuration for storing the given PRL or for otherwise minimizing a footprint of the given PRL; and these PRLs may exist in a substantially deployed (expanded) configuration for acting as a secure object storage location. Regardless of configuration (deployed or collapsed), PRLs may be removably attached to side-hinged-doors with the door-attachment-structure, in such a way so as not to impair operation of the given door. The PRLs may have various electronics for facilitating access (e.g., locking and unlocking the collapsible-locker), delivery confirmation, and mitigating theft. These electronics, along with specialized software, may allow an intended recipient (e.g., a buyer), a shipper/delivery person (or shipping/deliver robot), and/or a seller/vendor to access the PRL in a controlled and documented manner. At least some of these electronics may be in wireless communications with other electronic devices.