Hardware authentication based on PUFs and SHA-3 2nd round candidates

Security features are getting a growing interest in microelectronics. Not only entities have to authenticate in the context of a high secure communication but also the hardware employed has to be trusted. Silicon Physical Unclonable Functions (PUFs) or Physical Random Functions, which exploits manufacturing process variations in integrated circuits, have been used to authenticate the hardware in which they are included and, based on them, several cryptographic protocols have been reported. This paper describes the hardware implementation of a symmetric-key authentication protocol in which a PUF is one of the relevant blocks. The second relevant block is a SHA-3 2nd round candidate, a Secure Hash Algorithm (in particular Keccak), which has been proposed to replace the SHA-2 functions that have been broken no long time ago. Implementation details are discussed in the case of Xilinx FPGAs.Junta de Andalucía P08-TIC-03674Comunidad Europea FP7-INFSO-ICT-248858Ministerio de Ciencia y Tecnología TEC2008-04920 y DPI2008-0384

FPGA implementation and DPA resistance analysis of a lightweight HMAC construction based on photon hash family

Lightweight security is currently a challenge in the field of cryptography. Most of applications designed for embedded scenarios often focus on authentication or on providing some form of anonymity and/or privacy. A well-known cryptographic element employed to provide such security is the HMAC construction. However, reported solutions are not suitable for constrained-resource scenarios due to their heavy approaches optimized for high-speed operations. In order to cover this lack, a lightweight implementation of HMAC based on the Photon family of hash functions is given in this work. Security of the construction against differential power attacks (DPA) is analyzed using a SASEBO-II development board. Implementation and performance results for Xilinx Virtex-5 FPGAs of the HMAC structure is provide

Circuit authentication based on ring-oscillator PUFs

The use of Ring Oscillator PUFs to provide circuit authentication is analyzed in this paper. The limitations of the previously reported approach in terms of false rejection (due to high intra-die variations) and false acceptance (due to small inter-die variations) are discussed. These limitations are overcome by a new proposal that does not increase considerably hardware complexity and, besides, provides lower power consumption and/or higher speed to achieve high security requirements. All these issues are illustrated with experimental results obtained with FPGAs from Xilin

Improved Generation of Identifiers, Secret Keys, and Random Numbers From SRAMs

This paper presents a method to simultaneously improve the quality of the identifiers, secret keys, and random numbers that can be generated from the start-up values of standard static random access memories (SRAMs). The method is based on classifying memory cells after evaluating their start-up values at multiple measurements in a registration phase. The registration can be done without unplugging the device from its application context, and with no need for a complex laboratory setup. The method has been validated experimentally with standard low-power SRAM modules in two different application specific integrated circuits (ASICs) fabricated with the 90-nm TSMC technology. The results show that with a simple registration the length of the identifiers can be reduced by 45%, the worst case bit error probability (which defines the complexity of the error correcting code needed to recover a secret key) can be reduced by 64%, and the worst case minimum entropy value is improved, thus reducing the number of bits that have to be processed to obtain full entropy by 81%. The method can be applied to standard digital designs by controlling the external power supply to the SRAM using software or by incorporating simple circuitry in the design. In the latter case, a module for implementing the method in an ASIC designed in the 90-nm TSMC technology occupies an active area of 42, $025~mu text{m}^{mathrm {mathbf {2}}}

Using physical unclonable functions for hardware authentication: a survey

Physical unclonable functions (PUFs) are drawing a crescent interest in hardware oriented security due to their special characteristics of simplicity and safety. However, their nature as well as early stage of study makes them constitute currently a diverse and non-standardized set for designers. This work tries to establish one organization of existing PUF structures, giving guidelines for their choice, conditioning, and adaptation depending on the target application. In particular, it is described how using PUFs adequately could enlighten significantly most of the security primitives, making them very suitable for authenticating constrained resource platforms.Junta de Andalucía P08-TIC-03674Comunidad Europea FP7-INFSO-ICT-248858Ministerio de Ciencia y Tecnología TEC2008-04920, DPI2008-03847 y TEC2007-6510

Reducing bit flipping problems in SRAM physical unclonable functions for chip identification

Physical Unclonable functions (PUFs) have appeared as a promising solution to provide security in hardware. SRAM PUFs offer the advantage, over other PUF constructions, of reusing resources (memories) that already exist in many designs. However, their intrinsic noisy nature produces the so called bit flipping effect, which is a problem in circuit identification and secret key generation. The approaches reported to reduce this effect usually resort to the use of pre- and post-processing steps (such as Fuzzy Extractor structures combined with Error Correcting Codes), which increase the complexity of the system. This paper proposes a pre-processing step that reduces bit flipping problems without increasing the hardware complexity. The proposal has been verified experimentally with 90-nm SRAMs included in digital application specific integrated circuits (ASICs).Junta de Andalucía P08-TIC-03674Ministerio de Economía y Competitividad TEC2011-24319Comunidad Europea FP7-INFSO-ICT-24885

Método y dispositivo para generar identificadores y números verdaderamente aleatorios

La presente invención tiene por objeto un método que consta de dos etapas: una primera etapa de clasificación de las celdas de memoria estáticas en dos conjuntos disjuntos según su comportamiento ante repetidas veces en que se conectan a alimentación tra

Tratamiento quirúrgico de la atresia de coanas

Choanal atresia is the most frecuent congenital anomaly of nasal development. It can be unilateral or bilateral, and according to it, it will give symptoms from the moment of the birth, or up to the adult age. The treatment is surgical, with several possible surgical approaches. We present the case of a patient with unilateral atresia, operated in our hospital, and we describe the technique usedLa atresia de coana es la anomalía congénita más frecuente del desarrollo nasal. Puede ser unilateral o bilateral, y según sea su localización, provocará síntomas desde el momento del nacimiento, o de manera continua hasta la edad adulta en el caso de que sea unilateral. El tratamiento es quirúrgico, con varias vías de abordaje posibles. Presentamos el caso de una paciente con atresia unilateral, operada en nuestro hospital, y describimos la técnica utilizada

Uso de la laringectomía horizontal supraglótica y laringectomía parcial supracricoídea como técnicas quirúrgicas en la estrategia de conservación de la laringe. Resultados oncológicos y funcionales

Introduction and objectives: There are surgical techniques that allow the fulfillment of the fundamental requirements on which the strategy of laryngeal conservation in the cancer of this location is based. Two of these techniques are supraglottic horizontal laryngectomy and partial supracricoid laryngectomy. In this paper, we intend to demonstrate that its use as a strategy of organ conservation in those patients, who meet the requirements for its indication, is fully valid. Method: We analyzed the oncological and functional results (decannulation, swallowing and aspiration) in the last 18 years of a group of patients with squamous carcinoma of the larynx, treated in our center with the two surgical techniques mentioned. Results: With the two techniques, we obtain survival averages and disease free periods, similar or superior to those obtained with the oncological treatments of laryngeal preservation and total laryngectomy. With regard to swallowing time mean, we did not find statistically significant differences between the two surgical techniques. With regard to aspiration, neck surgery was a negative factor for complete recovery of swallowing. Conclusions: We demonstrated that the oncological results are at least equal to those of the concomitant chemotherapy and total laryngectomy with much more satisfactory functional results for the patientsIntroducción y objetivos: Existen técnicas quirúrgicas que permiten cumplir los requerimientos fundamentales en los que se basa la estrategia de conservación laríngea en el cáncer de esta localización. Dos de estas técnicas son la laringectomía horizontal supraglótica (LHSG) y la laringectomía parcial supracricoídea (LPSC). En este trabajo pretendemos demostrar que su uso como estrategia de conservación de órgano en aquellos pacientes que cumplan los requerimientos para su indicación, está plenamente vigente. Método: Analizamos los resultados oncológicos y funcionales (decanulación, deglución y aspiración) en los últimos 18 años de un grupo de pacientes con carcinoma escamoso de laringe, tratados en nuestro centro con las dos técnicas quirúrgicas mencionadas. Resultados: Con las dos técnicas obtenemos promedios de supervivencia y períodos libres de enfermedad, similares o superiores a los obtenidos con los tratamientos oncológicos de preservación de la laringe y laringectomía total. Con respecto al tiempo medio de deglución normal, no encontramos diferencias estadísticamente significativas entre las dos técnicas quirúrgicas. Con respecto a la aspiración, la cirugía del cuello fue un factor negativo para la recuperación completa de la deglución. Conclusiones: Demostramos que los resultados oncológicos son por lo menos, iguales a los de la quimiorradioterapia concomitante y laringectomía total con unos resultados funcionales mucho más satisfactorios para los paciente