Objective Focusing on the s ecurity problem of authentication and confidentiality in the context of computer networks, a digital signature scheme was proposed based on the public key crypt osystem. Methods Firstly...Objective Focusing on the s ecurity problem of authentication and confidentiality in the context of computer networks, a digital signature scheme was proposed based on the public key crypt osystem. Methods Firstly, the course of digital signature based on the public key cryptosystem was given. Then, RSA and ELGamal schemes were de scribed respectively. They were the basis of the proposed scheme. Generalized EL Gamal type signature schemes were listed. After comparing with each other, one s cheme, whose Signature equation was (m+r)x=j+s modΦ(p) , was adopted in the des igning. Results Based on two well-known cryptographic assumpti ons, the factorization and the discrete logarithms, a digital signature scheme w as presented. It must be required that s' was not equal to p'q' in the signing p rocedure, because attackers could forge the signatures with high probabilities i f the discrete logarithms modulo a large prime were solvable. The variable publi c key “e” is used instead of the invariable parameter “3” in Harn's signatu re scheme to enhance the security. One generalized ELGamal type scheme made the proposed scheme escape one multiplicative inverse operation in the signing proce dure and one modular exponentiation in the verification procedure. Concl usion The presented scheme obtains the security that Harn's scheme was originally claimed. It is secure if the factorization and the discrete logarithm s are simultaneously unsolvable.展开更多
The discrete logarithm method is the foundation of many public key algorithms. However, one type of key, defined as a weak-key, reduces the security of public key cryptosystems based on the discrete logarithm method. ...The discrete logarithm method is the foundation of many public key algorithms. However, one type of key, defined as a weak-key, reduces the security of public key cryptosystems based on the discrete logarithm method. The weak-key occurs if the public key is a factor or multiple of the primitive element, in which case the user＇s private key is not needed but can be obtained based on the character of the public key. An algorithm is presented that can easily test whether there is a weak-key in the cryptosystem. An example is given to show that an attack can be completed for the Elgamal digital signature if a weak-key exists, therefore validating the danger of weak-keys. Methods are given to prevent the generation of these weak-keys.展开更多
In this paper,we present local functional law of the iterated logarithm for Cs?rg?-Révész type increments of fractional Brownian motion.The results obtained extend works of Gantert[Ann.Probab.,1993,21(2):104...In this paper,we present local functional law of the iterated logarithm for Cs?rg?-Révész type increments of fractional Brownian motion.The results obtained extend works of Gantert[Ann.Probab.,1993,21(2):1045-1049]and Monrad and Rootzén[Probab.Theory Related Fields,1995,101(2):173-192].展开更多
In this paper,we investigate the blow-up phenomenon for a class of logarithmic viscoelastic equations with delay and nonlocal terms under acoustic boundary conditions.Using the energy method,we prove that nontrivial s...In this paper,we investigate the blow-up phenomenon for a class of logarithmic viscoelastic equations with delay and nonlocal terms under acoustic boundary conditions.Using the energy method,we prove that nontrivial solutions with negative initial energy will blow up in finite time,and provide an upper bound estimate for the blow-up time.Additionally,we also derive a lower bound estimate for the blow-up time.展开更多
A non-orthogonal multiple access(NOMA) power allocation scheme on the basis of the sparrow search algorithm(SSA) is proposed in this work. Specifically, the logarithmic utility function is utilized to address the pote...A non-orthogonal multiple access(NOMA) power allocation scheme on the basis of the sparrow search algorithm(SSA) is proposed in this work. Specifically, the logarithmic utility function is utilized to address the potential fairness issue that may arise from the maximum sum-rate based objective function and the optical power constraints are set considering the non-negativity of the transmit signal, the requirement of the human eyes safety and all users' quality of service(Qo S). Then, the SSA is utilized to solve this optimization problem. Moreover, to demonstrate the superiority of the proposed strategy, it is compared with the fixed power allocation(FPA) and the gain ratio power allocation(GRPA) schemes. Results show that regardless of the number of users considered, the sum-rate achieved by SSA consistently outperforms that of FPA and GRPA schemes. Specifically, compared to FPA and GRPA schemes, the sum-rate obtained by SSA is increased by 40.45% and 53.44% when the number of users is 7, respectively. The proposed SSA also has better performance in terms of user fairness. This work will benefit the design and development of the NOMA-visible light communication(VLC) systems.展开更多
We consider large-time behaviors of weak solutions to the evolutionary p-Laplacian with logarithmic source of time-dependent coefficient.We find that the weak solutions may neither decay nor blow up,provided that the ...We consider large-time behaviors of weak solutions to the evolutionary p-Laplacian with logarithmic source of time-dependent coefficient.We find that the weak solutions may neither decay nor blow up,provided that the initial data u(·,t_(0))is on the Nehari manifold N:={v∈W_(0)^(1,p)(Ω):I(v,to)=0,||▽v||P^(P)≠0}.This is quite different from the known results that the weak solutions may blow up as,u(·,to)∈N^(+):={v∈W_(0)^(1,p)(Ω):I(v,t_(0))<0}and weak solutions may decay as u(·,t_(0))∈N^(+):={v∈W_(0)^(1,p)(Ω):I(v,t_(0))>0}.展开更多
In order to improve the security of the signature scheme, a digital signature based on two hard-solved problems is proposed. The discrete logarithm problem and the factoring problem are two well known hard- solved mat...In order to improve the security of the signature scheme, a digital signature based on two hard-solved problems is proposed. The discrete logarithm problem and the factoring problem are two well known hard- solved mathematical problems. Combining the E1Gamal scheme based on the discrete logarithm problem and the OSS scheme based on the factoring problem, a digital signature scheme based on these two cryptographic assumptions is proposed. The security of the proposed scheme is based on the difficulties of simultaneously solving the factoring problem and the discrete logarithm problem. So the signature scheme will be still secure under the situation that any one of the two hard-problems is solved. Compared with previous schemes, the proposed scheme is more efficient in terms of space storage, signature length and computation complexities.展开更多
Multi-proxy signature schemes allow the original signer to delegate his/her signing power to n proxy signers such that all proxy signers must corporately generate a valid proxy signature on behalf of the original sign...Multi-proxy signature schemes allow the original signer to delegate his/her signing power to n proxy signers such that all proxy signers must corporately generate a valid proxy signature on behalf of the original signer. We first propose a multi-proxy signature scheme based on discrete logarithms and then adapt it to the elliptic curve cryptosystem. With the integration of self-certified public-key systems and the message recovery signature schemes,our proposed schemes have the following advan-tages:(1) They do not require the signing message to be transmitted,since the verifier can recover it from the signature;(2) The authentication of the public keys,verification of the signature,and recovery of the message can be simultaneously carried out in a single logical step;(3) No certificate is needed for validating the public keys. Further,the elliptic curve variant with short key lengths especially suits the cryptographic applications with limited computing power and storage space,e.g.,smart cards. As compared with the previous work that was implemented with the certificate-based public-key systems,the proposed schemes give better performance in terms of communication bandwidth and computation efforts.展开更多
Circuit design of 32 bit logarithmic skip adder (LSA) is introduced to implement high performance,low power addition.ELM carry lookahead adder is included into groups of carry skip adder and the hybrid structure cost...Circuit design of 32 bit logarithmic skip adder (LSA) is introduced to implement high performance,low power addition.ELM carry lookahead adder is included into groups of carry skip adder and the hybrid structure costs 30% less hardware than ELM.At circuit level,a carry incorporating structure to include the primary carry input in carry chain and an 'and xor' structure to implement final sum logic in 32 bit LSA are designed for better optimization.For 5V,1μm process,32 bit LSA has a critical delay of 5 9ns and costs an area of 0 62mm 2,power consumption of 23mW at 100MHz.For 2 5V,0 25μm process,critical delay of 0 8ns,power dissipation of 5 2mW at 100MHz is simulated.展开更多
We present a method for constructing k-ary sequences over elliptic curves. Using the multiplicative character of order k of finite fields, we construct a family of k-ary pseudorandom elliptic curve sequences. The pseu...We present a method for constructing k-ary sequences over elliptic curves. Using the multiplicative character of order k of finite fields, we construct a family of k-ary pseudorandom elliptic curve sequences. The pseudorandom measures, such as the well-distribution measure, the correlation measure of order e, and the linear complexity are estimated by using certain character sums. Such sequences share the same order of magnitude on the well-distribution measure, the correlation measure of order e as the ＇truly＇ random sequences. The method indicates that it is possible to construct ＇good＇ pseudorandom sequences over elliptic curves widely used in public key cryptography.展开更多
A new sanitizable signature scheme is proposed, in which the security flaw of Miyazaki＇s sanitizable signature scheme SUMI-4 is improved. The new scheme overcomes the shortcomings of the original scheme SUM1-4 by usi...A new sanitizable signature scheme is proposed, in which the security flaw of Miyazaki＇s sanitizable signature scheme SUMI-4 is improved. The new scheme overcomes the shortcomings of the original scheme SUM1-4 by using sanitizable authorization certificates. The new scheme enables the primitive signer to limit the sanitizer＇s power and still satisfies the security request of sanitizable signature.展开更多
文摘Objective Focusing on the s ecurity problem of authentication and confidentiality in the context of computer networks, a digital signature scheme was proposed based on the public key crypt osystem. Methods Firstly, the course of digital signature based on the public key cryptosystem was given. Then, RSA and ELGamal schemes were de scribed respectively. They were the basis of the proposed scheme. Generalized EL Gamal type signature schemes were listed. After comparing with each other, one s cheme, whose Signature equation was (m+r)x=j+s modΦ(p) , was adopted in the des igning. Results Based on two well-known cryptographic assumpti ons, the factorization and the discrete logarithms, a digital signature scheme w as presented. It must be required that s' was not equal to p'q' in the signing p rocedure, because attackers could forge the signatures with high probabilities i f the discrete logarithms modulo a large prime were solvable. The variable publi c key “e” is used instead of the invariable parameter “3” in Harn's signatu re scheme to enhance the security. One generalized ELGamal type scheme made the proposed scheme escape one multiplicative inverse operation in the signing proce dure and one modular exponentiation in the verification procedure. Concl usion The presented scheme obtains the security that Harn's scheme was originally claimed. It is secure if the factorization and the discrete logarithm s are simultaneously unsolvable.
基金Supported by the National Key Basic Research and Development (973) Program (No. 2003CB314805) and the National Natural Science Foundation of China (No. 90304014)
文摘The discrete logarithm method is the foundation of many public key algorithms. However, one type of key, defined as a weak-key, reduces the security of public key cryptosystems based on the discrete logarithm method. The weak-key occurs if the public key is a factor or multiple of the primitive element, in which case the user＇s private key is not needed but can be obtained based on the character of the public key. An algorithm is presented that can easily test whether there is a weak-key in the cryptosystem. An example is given to show that an attack can be completed for the Elgamal digital signature if a weak-key exists, therefore validating the danger of weak-keys. Methods are given to prevent the generation of these weak-keys.
基金Supported by NSFC(Nos.11661025,12161024)Natural Science Foundation of Guangxi(Nos.2020GXNSFAA159118,2021GXNSFAA196045)+2 种基金Guangxi Science and Technology Project(No.Guike AD20297006)Training Program for 1000 Young and Middle-aged Cadre Teachers in Universities of GuangxiNational College Student's Innovation and Entrepreneurship Training Program(No.202110595049)。
文摘In this paper,we present local functional law of the iterated logarithm for Cs?rg?-Révész type increments of fractional Brownian motion.The results obtained extend works of Gantert[Ann.Probab.,1993,21(2):1045-1049]and Monrad and Rootzén[Probab.Theory Related Fields,1995,101(2):173-192].
基金supported by the National Natural Sciences Foundation of China(No.62363005)。
文摘In this paper,we investigate the blow-up phenomenon for a class of logarithmic viscoelastic equations with delay and nonlocal terms under acoustic boundary conditions.Using the energy method,we prove that nontrivial solutions with negative initial energy will blow up in finite time,and provide an upper bound estimate for the blow-up time.Additionally,we also derive a lower bound estimate for the blow-up time.
基金supported by the Cooperative Research Project between China Coal Energy Research Institute Co.,Ltd. and Xidian University (No.N-KY-HX-1101-202302-00725)the Key Research and Development Program of Shaanxi Province (No.2017ZDCXL-GY-06-02)。
文摘A non-orthogonal multiple access(NOMA) power allocation scheme on the basis of the sparrow search algorithm(SSA) is proposed in this work. Specifically, the logarithmic utility function is utilized to address the potential fairness issue that may arise from the maximum sum-rate based objective function and the optical power constraints are set considering the non-negativity of the transmit signal, the requirement of the human eyes safety and all users' quality of service(Qo S). Then, the SSA is utilized to solve this optimization problem. Moreover, to demonstrate the superiority of the proposed strategy, it is compared with the fixed power allocation(FPA) and the gain ratio power allocation(GRPA) schemes. Results show that regardless of the number of users considered, the sum-rate achieved by SSA consistently outperforms that of FPA and GRPA schemes. Specifically, compared to FPA and GRPA schemes, the sum-rate obtained by SSA is increased by 40.45% and 53.44% when the number of users is 7, respectively. The proposed SSA also has better performance in terms of user fairness. This work will benefit the design and development of the NOMA-visible light communication(VLC) systems.
文摘We consider large-time behaviors of weak solutions to the evolutionary p-Laplacian with logarithmic source of time-dependent coefficient.We find that the weak solutions may neither decay nor blow up,provided that the initial data u(·,t_(0))is on the Nehari manifold N:={v∈W_(0)^(1,p)(Ω):I(v,to)=0,||▽v||P^(P)≠0}.This is quite different from the known results that the weak solutions may blow up as,u(·,to)∈N^(+):={v∈W_(0)^(1,p)(Ω):I(v,t_(0))<0}and weak solutions may decay as u(·,t_(0))∈N^(+):={v∈W_(0)^(1,p)(Ω):I(v,t_(0))>0}.
基金The National Natural Science Foundation of China(No60402019)the Science Research Program of Education Bureau of Hubei Province (NoQ200629001)
文摘In order to improve the security of the signature scheme, a digital signature based on two hard-solved problems is proposed. The discrete logarithm problem and the factoring problem are two well known hard- solved mathematical problems. Combining the E1Gamal scheme based on the discrete logarithm problem and the OSS scheme based on the factoring problem, a digital signature scheme based on these two cryptographic assumptions is proposed. The security of the proposed scheme is based on the difficulties of simultaneously solving the factoring problem and the discrete logarithm problem. So the signature scheme will be still secure under the situation that any one of the two hard-problems is solved. Compared with previous schemes, the proposed scheme is more efficient in terms of space storage, signature length and computation complexities.
基金Project (No. 94-2213-E-182-019) supported by the National Science Council, Taiwan, China
文摘Multi-proxy signature schemes allow the original signer to delegate his/her signing power to n proxy signers such that all proxy signers must corporately generate a valid proxy signature on behalf of the original signer. We first propose a multi-proxy signature scheme based on discrete logarithms and then adapt it to the elliptic curve cryptosystem. With the integration of self-certified public-key systems and the message recovery signature schemes,our proposed schemes have the following advan-tages:(1) They do not require the signing message to be transmitted,since the verifier can recover it from the signature;(2) The authentication of the public keys,verification of the signature,and recovery of the message can be simultaneously carried out in a single logical step;(3) No certificate is needed for validating the public keys. Further,the elliptic curve variant with short key lengths especially suits the cryptographic applications with limited computing power and storage space,e.g.,smart cards. As compared with the previous work that was implemented with the certificate-based public-key systems,the proposed schemes give better performance in terms of communication bandwidth and computation efforts.
文摘Circuit design of 32 bit logarithmic skip adder (LSA) is introduced to implement high performance,low power addition.ELM carry lookahead adder is included into groups of carry skip adder and the hybrid structure costs 30% less hardware than ELM.At circuit level,a carry incorporating structure to include the primary carry input in carry chain and an 'and xor' structure to implement final sum logic in 32 bit LSA are designed for better optimization.For 5V,1μm process,32 bit LSA has a critical delay of 5 9ns and costs an area of 0 62mm 2,power consumption of 23mW at 100MHz.For 2 5V,0 25μm process,critical delay of 0 8ns,power dissipation of 5 2mW at 100MHz is simulated.
基金Supported by the National Natural Science Foundation of China (61063041)the Program for New Century Excellent Talents in Fujian Province University (JK2010047)the Open Funds of State Key Laboratory of Information Security (01-01-1)
文摘We present a method for constructing k-ary sequences over elliptic curves. Using the multiplicative character of order k of finite fields, we construct a family of k-ary pseudorandom elliptic curve sequences. The pseudorandom measures, such as the well-distribution measure, the correlation measure of order e, and the linear complexity are estimated by using certain character sums. Such sequences share the same order of magnitude on the well-distribution measure, the correlation measure of order e as the ＇truly＇ random sequences. The method indicates that it is possible to construct ＇good＇ pseudorandom sequences over elliptic curves widely used in public key cryptography.
基金Supported by the National Natural Science Foundation of China (60273268)the Key Project of Ministry of Education, China (208139)
文摘A new sanitizable signature scheme is proposed, in which the security flaw of Miyazaki＇s sanitizable signature scheme SUMI-4 is improved. The new scheme overcomes the shortcomings of the original scheme SUM1-4 by using sanitizable authorization certificates. The new scheme enables the primitive signer to limit the sanitizer＇s power and still satisfies the security request of sanitizable signature.
