Despite Kerckhoff’s principle,there are secret ciphers with unknown components for diplomatic or military usages.The side-channel analysis of reverse engineering(SCARE)is developed for analyzing secret ciphers.Consid...Despite Kerckhoff’s principle,there are secret ciphers with unknown components for diplomatic or military usages.The side-channel analysis of reverse engineering(SCARE)is developed for analyzing secret ciphers.Considering the side-channel leakage,SCARE attacks enable the recovery of some secret parts of a cryptosystem,e.g.,the substitution box table.However,based on idealized leakage assumption,most of these attacks have a few limitations on prior knowledge or implementations.In this paper,we focus on AES-like block ciphers with a secret S-box and demonstrate an attack which recovers both the secret key and the secret S-box.On the one hand,the key is recovered under profiled circumstance by leakage analysis and collision attack.On the other hand,the SCARE attack is based on mathematical analysis.It relies on Hamming weight of MixColumns intermediate results in the first round,which can restore the secret S-box.Experiments are performed on real power traces from a software implementation of AES-like block cipher.Moreover,we evaluate the soundness and efficiency of our method by simulations and compare with previous approaches.Our method has more advantages in intermediate results location and the required number of traces.For simulated traces with gaussian noise,our method requires 100000 traces to fully restore the secret S-box,while the previous method requires nearly 300000 traces to restore S-box.展开更多
China steps up a clampdown on the financing vehicles of local governments control over local governments’ financing vehicles will be tightened to fend off what some economists warn could turn into a
Background:The first web space not only plays an integral role in hand functionality,but also holds an important aesthetic function for patients with cicatricial contractures,which hinders the ability to move joints,t...Background:The first web space not only plays an integral role in hand functionality,but also holds an important aesthetic function for patients with cicatricial contractures,which hinders the ability to move joints,thereby restricting the performance of everyday activities.Therefore,a wide variety of reconstruction options are available.In this study,our main aim was to have a clear surgical plan prior to surgery according to preoperative findings and the degree of thumb abduction span.Methods:This study was conducted at Kasr Al-Ainy Hospital.This cohort study included 33 patients with cicatricial first web space contractures who underwent reconstructive procedures to restore the first web space.Patients were assessed preoperatively and categorized according to the degree of contracture,and the reconstruction procedure was chosen accordingly.They were assessed using both objective and subjective methods.Results:In this study,33 cases of cicatricial contracture of the first web space due to physical or thermal trauma were included.Measurements of the change in the span of abduction were performed for all patients included in the study preoperatively and postoperatively.Skin grafting and skin substitutes had an average change in abduction span of 32.5°(±14.4°),Z-plasty release had a mean of 30.59°(±8.82°)increase in abduction span,regional flaps had an increase of 40.71°(±12.39°),while distant flaps had an increase of 35°(±3.54°).Conclusion:No single reconstruction method can be used in all cases.When viewing a patient,one must consider that each individual has a unique representation.However,if we follow a systematic method for the initial evaluation,the most efficient flap can be chosen for each case,thus reducing the need for secondary procedures.Categorizing the cases according to the abduction span into mild,moderate,or severe forms is the first building block of this algorithm.Adjacent tissue condition,patient occupation,compliance,and the need to return to work are important factors.展开更多
基金supported by the National Natural Science Foundation of China(Grant Nos.61872040,U1836101,61871037,62002021)National Cryptography Development Fund(MMJ20170201)Beijing Natural Science Foundation(4202070).
文摘Despite Kerckhoff’s principle,there are secret ciphers with unknown components for diplomatic or military usages.The side-channel analysis of reverse engineering(SCARE)is developed for analyzing secret ciphers.Considering the side-channel leakage,SCARE attacks enable the recovery of some secret parts of a cryptosystem,e.g.,the substitution box table.However,based on idealized leakage assumption,most of these attacks have a few limitations on prior knowledge or implementations.In this paper,we focus on AES-like block ciphers with a secret S-box and demonstrate an attack which recovers both the secret key and the secret S-box.On the one hand,the key is recovered under profiled circumstance by leakage analysis and collision attack.On the other hand,the SCARE attack is based on mathematical analysis.It relies on Hamming weight of MixColumns intermediate results in the first round,which can restore the secret S-box.Experiments are performed on real power traces from a software implementation of AES-like block cipher.Moreover,we evaluate the soundness and efficiency of our method by simulations and compare with previous approaches.Our method has more advantages in intermediate results location and the required number of traces.For simulated traces with gaussian noise,our method requires 100000 traces to fully restore the secret S-box,while the previous method requires nearly 300000 traces to restore S-box.
文摘China steps up a clampdown on the financing vehicles of local governments control over local governments’ financing vehicles will be tightened to fend off what some economists warn could turn into a
文摘Background:The first web space not only plays an integral role in hand functionality,but also holds an important aesthetic function for patients with cicatricial contractures,which hinders the ability to move joints,thereby restricting the performance of everyday activities.Therefore,a wide variety of reconstruction options are available.In this study,our main aim was to have a clear surgical plan prior to surgery according to preoperative findings and the degree of thumb abduction span.Methods:This study was conducted at Kasr Al-Ainy Hospital.This cohort study included 33 patients with cicatricial first web space contractures who underwent reconstructive procedures to restore the first web space.Patients were assessed preoperatively and categorized according to the degree of contracture,and the reconstruction procedure was chosen accordingly.They were assessed using both objective and subjective methods.Results:In this study,33 cases of cicatricial contracture of the first web space due to physical or thermal trauma were included.Measurements of the change in the span of abduction were performed for all patients included in the study preoperatively and postoperatively.Skin grafting and skin substitutes had an average change in abduction span of 32.5°(±14.4°),Z-plasty release had a mean of 30.59°(±8.82°)increase in abduction span,regional flaps had an increase of 40.71°(±12.39°),while distant flaps had an increase of 35°(±3.54°).Conclusion:No single reconstruction method can be used in all cases.When viewing a patient,one must consider that each individual has a unique representation.However,if we follow a systematic method for the initial evaluation,the most efficient flap can be chosen for each case,thus reducing the need for secondary procedures.Categorizing the cases according to the abduction span into mild,moderate,or severe forms is the first building block of this algorithm.Adjacent tissue condition,patient occupation,compliance,and the need to return to work are important factors.
