ACFA: Secure Runtime Auditing & Guaranteed Device Healing via Active Control Flow Attestation

Low-end embedded devices are increasingly used in various smart applications and spaces. They are implemented under strict cost and energy budgets, using microcontroller units (MCUs) that lack security features available in general-purpose processors. In this context, Remote Attestation (RA) was proposed as an inexpensive security service to enable a verifier (Vrf) to remotely detect illegal modifications to a software binary installed on a low-end prover MCU (Prv). Since attacks that hijack the software's control flow can evade RA, Control Flow Attestation (CFA) augments RA with information about the exact order in which instructions in the binary are executed, enabling detection of control flow attacks. We observe that current CFA architectures can not guarantee that Vrf ever receives control flow reports in case of attacks. In turn, while they support exploit detection, they provide no means to pinpoint the exploit origin. Furthermore, existing CFA requires either binary instrumentation, incurring significant runtime overhead and code size increase, or relatively expensive hardware support, such as hash engines. In addition, current techniques are neither continuous (only meant to attest self-contained operations) nor active (offer no secure means to remotely remediate detected compromises). To jointly address these challenges, we propose ACFA: a hybrid (hardware/software) architecture for Active CFA. ACFA enables continuous monitoring of all control flow transfers in the MCU and does not require binary instrumentation. It also leverages the recently proposed concept of Active Roots-of-Trust to enable secure auditing of vulnerability sources and guaranteed remediation when a compromise is detected. We provide an open-source reference implementation of ACFA on top of a commodity low-end MCU (TI MSP430) and evaluate it to demonstrate its security and cost-effectiveness

In silico mapping of essential residues in the catalytic domain of PDE5 responsible for stabilization of its commercial inhibitors

Phosphodiesterase type 5 (PDE5) is an important enzyme associated with the hydrolysis of cyclic guanosine monophosphate (cGMP) to guanosine monophosphate (GMP). Due to the relevant role of second messenger cGMP as a mediator in many physiological processes, efforts have been converged to find a safe pharmacological approach, seeking a specific, selective and potent inhibitor of the PDE5 enzyme. There are five commercial drugs with potential for clinical use: tadalafil, sildenafil, avanafil, udenafil and vardenafil. Here, we applied molecular modeling to obtain different profiles of protein-ligand interactions by adopting distinct PDE5 structures, specifically PDBid:1XOZ and two extracted from molecular dynamics (MD) simulations. The results generated by molecular docking showed several possibilities for inhibitor interactions with the catalytic pocket. Tadalafil, sildenafil and vardenafil were clearly stabilized by Gln817 via a well-oriented hydrogen bond. Another set of different interactions, such as polar, hydrophobic, pi-stacking, metal-ligand and electrostatic, were responsible for accommodating avanafil and udenafil. All of the ligands are discussed in detail with consideration of the distinct protein structures, and a profile of the probability of residue-ligand contact is suggested, with the most frequently observed being: Tyr612, His613, Ser661, Thr723, Asp724, Asp764, Leu765, Val782 and Phe786. The molecular interactions displayed herein confirm findings achieved by previous authors and also present new contacts. In addition, the discussion can help researchers obtain a molecular basis for planning new selective PDE5 inhibitors, as well as explain an inhibitor's experimental assays by considering the specific interactions occurring at the catalytic site874CONSELHO NACIONAL DE DESENVOLVIMENTO CIENTÍFICO E TECNOLÓGICO - CNPQFUNDAÇÃO DE AMPARO À PESQUISA DO ESTADO DE SÃO PAULO - FAPESP470374/2013-62010/16947-9; 2013/05475-7; 2013/08293-7; 2013/22360-9; 2017/26687-3; 2017/02201-

EDUCAÇÃO INTERDISCIPLINARIEDADE E TRANSDISCIPLINARIEDADE

Este trabalho procura apresentar algumas idéias sobre interdisciplinariedade e transdiciplinariedade na educação. Interdisciplinariedade é a síntese de duas ou mais disciplinas, enquanto que a transdisciplinariedade seria o reconhecimento da interdependência entre vários aspectos da realidade. É a conseqüência normal da síntese dialética provocada pela interdisciplinariedade bem-sucedida. A transdisciplinariedade explica um construto pelos métodos do outro. Uma ciência se torna objeto de outra. Assim, por exemplo, o conteúdo da química será exposto nos termos da metodologia da biologia, ou vice-versa. Mediante este procedimento, o químico se dará conta de seus comportamentos, pois é isto que interessa. O papel da escola é garantir o movimento, o fluxo de energia, a riqueza do processo - o que significa a manutenção de um diálogo permanente de acordo com o que acontece em cada momento -, propor situações problemas, desafios, desencadear reflexões, estabelecer conexões entre o conhecimento adquirido e os novos conceitos, entre o ocorrido e o pretendido, de tal modo que as invenções sejam adequadas ao estilo do aluno, as condições intelectuais e emocionais e à situação contextual