Critical resource sharing among multiple entities in a processing system is inevitable, which in turn calls for the presence of appropriate authentication and access control mechanisms. Generally speaking, these mecha...
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ISBN:
(纸本)9781450347020
Critical resource sharing among multiple entities in a processing system is inevitable, which in turn calls for the presence of appropriate authentication and access control mechanisms. Generally speaking, these mechanisms are implemented via trusted software "policy checkers" that enforce certain high level application-specific "rules" to enforce a policy. Whether implemented as operating system modules or embedded inside the application ad hoc, these policy checkers expose additional attack surface in addition to the application logic. In order to protect application software from an adversary, modern secure processing platforms, such as Intel's Software Guard Extensions (SGX), employ principled hardware isolation to offer secure software containers or enclaves to execute trusted sensitive code with some integrity and privacy guarantees against a privileged software adversary. We extend this model further and propose using these hardware isolation mechanisms to shield the authentication and access control logic essential to policy checker software. While relying on the fundamental features of modern secure processors, our framework introduces productive software design guidelines which enable a guarded environment to execute sensitive policy checking code - hence enforcing application control flow integrity - and afford flexibility to the application designer to construct appropriate high-level policies to customize policy checker software.
This paper presents the theoretical blueprint of a new secure token called the Externalized Microprocessor (XmuP). Unlike a smartcard, the XmuP contains no ROM at all. While exporting all the device's executable c...
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ISBN:
(纸本)3540226664
This paper presents the theoretical blueprint of a new secure token called the Externalized Microprocessor (XmuP). Unlike a smartcard, the XmuP contains no ROM at all. While exporting all the device's executable code to potentially untrustworthy terminals poses formidable security problems, the advantages of ROM-less secure tokens are numerous: chip masking time disappears, bug patching becomes a mere terminal update and hence does not imply any roll-out of cards in the field. Most importantly, code size ceases to be a limiting factor. This is particularly significant given the steady increase in on-board software complexity. After describing the machine's instruction-set we introduce a public-key oriented architecture design which relies on a new RSA screening scheme and features a relatively low communication overhead. We propose two protocols that execute and dynamically authenticate arbitrary programs, provide a strong security model for these protocols and prove their security under appropriate complexity assumptions.
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