A cryptographic ransomware is a malware that encrypts applications and data. The files become inaccessible, and cannot be decrypted unless one knows the decryption key. For this decryption service, the ransomware asks for money, but there is no assurance that the service will be delivered: ransomware can threaten psychologically the victims for more or leave them in trouble. The economic damage is huge, estimated to reach 11.5 billion of dollars in 2019 and in US only. We have a solution to block cryptographically strong ransomware before it starts encrypting, that is before any damage is done. We gave it the working name of USHALLNOTPASS, and we have evidence already that it is effective against ransomware that, at today, are still considered unstoppable, like NotPetya.We claim that USHALLNOT pass is secure (i.e., no false negative, in the set of targeted ransomware); efficient (i.e., very low computational overhead); effective (i.e., no false positive in the medium range); usable (i.e., not interfering with the normal user experience at their devices); and adaptive (i.e., working against zero-day ransomware). All such claims will be proven thanks to this Proof-of-Concept project. We will implement prototypes of USHALLNOT working for Windows 7 and Windows 10 and test it intensively for efficiency, effectiveness, and usability.Integrated with traditional anti-malware systems, USHALLNOTPASS will enable stronger, more efficient and effective, defenses against the this extremely disrupting threat.