A technique of proofing against tampering with a computer including a chassis with a plurality of fasteners. The technique includes obtaining by the computer data indicative of a sequence of implication events associated with the fasteners of the plurality of fasteners, generating a pattern corresponding to the sequence of implication events, matching between data corresponding to the generated pattern and a reference data, and initiating one or more anti-tampering actions responsive to a mismatching result. The method can further include generating a cryptographic signature corresponding to the generated pattern, wherein matching between data corresponding to the generated pattern and the reference data includes matching the generated cryptographic signature to a cryptographic reference corresponding to the reference data. Alternatively, or additionally, the generated cryptographic signature can be usable for secure access to information stored on the computer.