Decades went by since Mark Weiser published his influential work on the computer of the 21st century. Over the years, some of the UbiComp features presented in that paper have been gradually adopted by industry players in the technology market. While this technological evolution resulted in many benefits to our society, it has also posed, along the way, countless challenges that we have yet to surpass. In this paper, we address major challenges from areas that most afflict the UbiComp revolution: 1. Software Protection: weakly typed languages, polyglot software, and networked embedded systems. 2. Long-term Security: recent advances in cryptanalysis and quantum attacks. 3. Cryptography Engineering: lightweight cryptosystems and their secure implementation. 4. Resilience: issues related to service availability and the paramount role of resilience. 5. Identity Management: requirements to identity management with invisibility. 6. Privacy Implications: sensitivity data identification and regulation. 7. Forensics: trustworthy evidence from the synergy of digital and physical world. We point out directions towards the solutions of those problems and claim that if we get all this right, we will turn the science fiction of UbiComp into science fact.