Add to ORKGAbstract. PKCS#11 is a very popular cryptographic API: it is the standard used by many Hardware Security Modules, smartcards and software cryptographic tokens. Several attacks have been uncovered against PKCS#11 at different levels: intrinsic logical flaws, cryptographic vulnerabilities or severe compliance issues. Since affected hardware remains widespread in computer infrastructures, we propose a user-centric and pragmatic approach for secure usage of vulnerable devices. We introduce Caml Crush, a PKCS#11 filtering proxy. Our solution allows to dynamically protect PKCS#11 cryptographic tokens from state of the art attacks. This is the first approach that is immediately applicable to commercially available products. We provide a fully func...