We design a practical and provablysecure block ciper over small domain and non-binary inputs,which is also can be considered as a pseudorandom permutation on N elements.Our work is based on a relation we found between...We design a practical and provablysecure block ciper over small domain and non-binary inputs,which is also can be considered as a pseudorandom permutation on N elements.Our work is based on a relation we found between the small domain ciper and the negative hypergeometric probability(NHG) distribution.We prove that our block ciper achieves ideal security,that is,it is indistinguishable from a random permutation even if the adversary had already observed N plaintext-cipertext pairs.In particular,we initiate an efficient and sufficiently precise sampling algorithm for negative hypergeometric distribution.展开更多
In this paper, a new quantum images encoding scheme is proposed. The proposed scheme mainly consists of four different encoding algorithms. The idea behind of the scheme is a binary key generated randomly for each pix...In this paper, a new quantum images encoding scheme is proposed. The proposed scheme mainly consists of four different encoding algorithms. The idea behind of the scheme is a binary key generated randomly for each pixel of the original image. Afterwards, the employed encoding algorithm is selected corresponding to the qubit pair of the generated randomized binary key. The security analysis of the proposed scheme proved its enhancement through both randomization of the generated binary image key and altering the gray-scale value of the image pixels using the qubits of randomized binary key. The simulation of the proposed scheme assures that the final encoded image could not be recognized visually. Moreover, the histogram diagram of encoded image is flatter than the originM one. The Shannon entropies of the final encoded images are significantly higher than the original one, which indicates that the attacker can not gain any information about the encoded images.展开更多
The system energy of H atom occupying different positions in Cr2O3 crystal lattice is calculated by adopting the first-principles calculation method based on density functional theory in this paper. The results indica...The system energy of H atom occupying different positions in Cr2O3 crystal lattice is calculated by adopting the first-principles calculation method based on density functional theory in this paper. The results indicate that the most stable position of H atom in Cr2O3 crystal lattice locates at the bilateral positions of the center of the unoccupied O octahedral interstice. The reason resulting in this situation is analyzed by comparing the change of Cr2O3 lattice distortion and density of states in Cr2O3_H system when H atom locates at different positions in octahedral interstice. The diffusion activation energy of H atom is 0.73 eV,which is determined by seeking the diffusion path and transition state of H atom in Cr2O3 crystal lattice. The effective attempt frequency of H atom in Cr2O3 crystal lattice is also calculated by using molecular dynamics. Combining with diffusion activation energy data,the diffusion coefficient of H atom in Cr2O3 crystal is determined.展开更多
基金National 973 Fundamental Basic Research Program under grant No.2014CB340600 and by the National Natural Science Foundations of China
文摘We design a practical and provablysecure block ciper over small domain and non-binary inputs,which is also can be considered as a pseudorandom permutation on N elements.Our work is based on a relation we found between the small domain ciper and the negative hypergeometric probability(NHG) distribution.We prove that our block ciper achieves ideal security,that is,it is indistinguishable from a random permutation even if the adversary had already observed N plaintext-cipertext pairs.In particular,we initiate an efficient and sufficiently precise sampling algorithm for negative hypergeometric distribution.
基金Supported by Kermanshah Branch,Islamic Azad University,Kermanshah,IRAN
文摘In this paper, a new quantum images encoding scheme is proposed. The proposed scheme mainly consists of four different encoding algorithms. The idea behind of the scheme is a binary key generated randomly for each pixel of the original image. Afterwards, the employed encoding algorithm is selected corresponding to the qubit pair of the generated randomized binary key. The security analysis of the proposed scheme proved its enhancement through both randomization of the generated binary image key and altering the gray-scale value of the image pixels using the qubits of randomized binary key. The simulation of the proposed scheme assures that the final encoded image could not be recognized visually. Moreover, the histogram diagram of encoded image is flatter than the originM one. The Shannon entropies of the final encoded images are significantly higher than the original one, which indicates that the attacker can not gain any information about the encoded images.
基金supported by the National Natural Science Foundation of China (Grant Nos.50771104,50871122)
文摘The system energy of H atom occupying different positions in Cr2O3 crystal lattice is calculated by adopting the first-principles calculation method based on density functional theory in this paper. The results indicate that the most stable position of H atom in Cr2O3 crystal lattice locates at the bilateral positions of the center of the unoccupied O octahedral interstice. The reason resulting in this situation is analyzed by comparing the change of Cr2O3 lattice distortion and density of states in Cr2O3_H system when H atom locates at different positions in octahedral interstice. The diffusion activation energy of H atom is 0.73 eV,which is determined by seeking the diffusion path and transition state of H atom in Cr2O3 crystal lattice. The effective attempt frequency of H atom in Cr2O3 crystal lattice is also calculated by using molecular dynamics. Combining with diffusion activation energy data,the diffusion coefficient of H atom in Cr2O3 crystal is determined.
