In ACM'CCS 2009,Camenisch,et al.proposed the Oblivious Transfer with Access Control(AC-OT) in which each item is associated with an attribute set and can only be available,on request,to the users who have all the ...In ACM'CCS 2009,Camenisch,et al.proposed the Oblivious Transfer with Access Control(AC-OT) in which each item is associated with an attribute set and can only be available,on request,to the users who have all the attributes in the associated set.Namely,AC-OT achieves access control policy for conjunction of attributes.Essentially,the functionality of AC-OT is equivalent to the sim-plified version that we call AC-OT-SV:for each item,one attribute is associated with it,and it is requested that only the users who possess the associated attribute can obtain the item by queries.On one hand,AC-OT-SV is a special case of AC-OT when there is just one associated attribute with each item.On the other hand,any AC-OT can be realized by an AC-OT-SV.In this paper,we first present a concrete AC-OT-SV protocol which is proved to be secure in the model defined by Camenisch,et al..Then from the protocol,interestingly,a concrete Identity-Based Encryption(IBE) with Anonymous Key Issuing(AKI) is given which is just a direct application to AC-OT-SV.By comparison,we show that the AKI protocol we present is more efficient in communications than that proposed by Chow.展开更多
The theory of quadratic residues plays an important role in cryptography.In 2001,Cocks developed an identity-based encryption(IBE)scheme based on quadratic residues,resolving Shamir’s 17-year-old open problem.However...The theory of quadratic residues plays an important role in cryptography.In 2001,Cocks developed an identity-based encryption(IBE)scheme based on quadratic residues,resolving Shamir’s 17-year-old open problem.However,a notable drawback of Cocks’scheme is the significant expansion of the ciphertext,and some of its limitations have been addressed in subsequent research.Recently,Cotan and Teşeleanu highlighted that previous studies on Cocks’scheme relied on a trial-and-error method based on Jacobi symbols to generate the necessary parameters for the encryption process.They enhanced the encryption speed of Cocks’scheme by eliminating this trialand-error method.Based on security analysis,this study concludes that the security of Cotan-Teşeleanu’s proposal cannot be directly derived from the security of the original Cocks’scheme.Furthermore,by adopting the Cotan-Teşeleanu method and introducing an additional variable as a public element,this study develops a similar enhancement scheme that not only accelerates the encryption speed but also provides security equivalent to the original Cocks’scheme.展开更多
Attribute-based encryption(ABE)is a cryptographic framework that provides flexible access control by allowing encryption based on user attributes.ABE is widely applied in cloud storage,file sharing,e-Health,and digita...Attribute-based encryption(ABE)is a cryptographic framework that provides flexible access control by allowing encryption based on user attributes.ABE is widely applied in cloud storage,file sharing,e-Health,and digital rightsmanagement.ABE schemes rely on hard cryptographic assumptions such as pairings and others(pairingfree)to ensure their security against external and internal attacks.Internal attacks are carried out by authorized users who misuse their access to compromise security with potentially malicious intent.One common internal attack is the attribute collusion attack,in which users with different attribute keys collaborate to decrypt data they could not individually access.This paper focuses on the ciphertext-policy ABE(CP-ABE),a type of ABE where ciphertexts are produced with access policies.Our firstwork is to carry out the attribute collusion attack against several existing pairingfree CP-ABE schemes.As a main contribution,we introduce a novel attack,termed the anonymous key-leakage attack,concerning the context in which users could anonymously publish their secret keys associated with certain attributes on public platforms without the risk of detection.This kind of internal attack has not been defined or investigated in the literature.We then show that several prominent pairing-based CP-ABE schemes are vulnerable to this attack.We believe that this work will contribute to helping the community evaluate suitable CP-ABE schemes for secure deployment in real-life applications.展开更多
This paper describes two identity-based broadcast encryption （IBBE） schemes for mobile ad hoc networks. The first scheme proposed achieves sub-linear size cipertexts and the second scheme achieves O（1）- size ciphe...This paper describes two identity-based broadcast encryption （IBBE） schemes for mobile ad hoc networks. The first scheme proposed achieves sub-linear size cipertexts and the second scheme achieves O（1）- size ciphertexts. Furthermore, when the public keys are transmitted, the two schemes have short transmissions and achieve O（1） user storage cost, which are important for a mobile ad hoc network. Finally, the proposed schemes are provable security under the decision generalized bilinear Diffi-Hellman （GBDH） assumption in the random oracles model.展开更多
An identity-based encryption(IBE) was studied with non-interactively opening property that the plain text of a ciphertext can be revealed without affecting the security of the encryption system.Two kinds of non-intera...An identity-based encryption(IBE) was studied with non-interactively opening property that the plain text of a ciphertext can be revealed without affecting the security of the encryption system.Two kinds of non-interactive opening properties for IBE schemes were defined along with a concrete scheme in each case.展开更多
In this paper,we show how to use the dual techniques in the subgroups to give a secure identity-based broadcast encryption(IBBE) scheme with constant-size ciphertexts. Our scheme achieves the full security(adaptive se...In this paper,we show how to use the dual techniques in the subgroups to give a secure identity-based broadcast encryption(IBBE) scheme with constant-size ciphertexts. Our scheme achieves the full security(adaptive security) under three static(i.e. non q-based) assumptions. It is worth noting that only recently Waters gives a short ciphertext broadcast encryption system that is even adaptively secure under the simple assumptions. One feature of our methodology is that it is relatively simple to leverage our techniques to get adaptive security.展开更多
This paper proposes an identity-based encryption scheme with the help of bilinear pairings, where the identity information of a user functions as the user＇s public key. The advantage of an identity-based public key s...This paper proposes an identity-based encryption scheme with the help of bilinear pairings, where the identity information of a user functions as the user＇s public key. The advantage of an identity-based public key system is that it can avoid public key certificates and certificate management. Our identity-based encryption scheme enjoys short ciphertexts and provable security against chosen-ciphertext attack （CCA）.展开更多
Broadcast encryption (BE) allows a sender to broadcast its message to a set of receivers in a single ciphertext. However, in broadcast encryption scheme, ciphertext length is always related to the size of the receiver...Broadcast encryption (BE) allows a sender to broadcast its message to a set of receivers in a single ciphertext. However, in broadcast encryption scheme, ciphertext length is always related to the size of the receiver set. Thus, how to improve the communication of broadcast encryption is a big issue. In this paper, we proposed an identity-based homomorphic broadcast encryption scheme which supports an external entity to directly calculate ciphertexts and get a new ciphertext which is the corresponding result of the operation on plaintexts without decrypting them. The correctness and security proofs of our scheme were formally proved. Finally, we implemented our scheme in a simulation environment and the experiment results showed that our scheme is efficient for practical applications.展开更多
Identity-Based Encryption (IBE) has seen limited adoption, largely due to the absolute trust that must be placed in the private key generator (PKG)—an authority that computes the private keys for all the users in the...Identity-Based Encryption (IBE) has seen limited adoption, largely due to the absolute trust that must be placed in the private key generator (PKG)—an authority that computes the private keys for all the users in the environment. Several constructions have been proposed to reduce the trust required in the PKG (and thus preserve the privacy of users), but these have generally relied on unrealistic assumptions regarding non-collusion between various entities in the system. Unfortunately, these constructions have not significantly improved IBE adoption rates in real-world environments. In this paper, we present a construction that reduces trust in the PKG without unrealistic non-collusion assumptions. We achieve this by incorporating a novel combination of digital credential technology and bilinear maps, and making use of multiple randomly-chosen entities to complete certain tasks. The main result and primary contribution of this paper are a thorough security analysis of this proposed construction, examining the various entity types, attacker models, and collusion opportunities in this environment. We show that this construction can prevent, or at least mitigate, all considered attacks. We conclude that our construction appears to be effective in preserving user privacy and we hope that this construction and its security analysis will encourage greater use of IBE in real-world environments.展开更多
A recent proposal by Adams integrates the digital credentials (DC) technology of Brands with the identity-based encryption (IBE) technology of Boneh and Franklin to create an IBE scheme that demonstrably enhances priv...A recent proposal by Adams integrates the digital credentials (DC) technology of Brands with the identity-based encryption (IBE) technology of Boneh and Franklin to create an IBE scheme that demonstrably enhances privacy for users. We refer to this scheme as a privacy-preserving identity-based encryption (PP-IBE) construction. In this paper, we discuss the concrete implementation considerations for PP-IBE and provide a detailed instantiation (based on q-torsion groups in supersingular elliptic curves) that may be useful both for proof-of-concept purposes and for pedagogical purposes.展开更多
Identity-based encryption with equality test(IBEET)is proposed to check whether the underlying messages of ciphertexts,even those encrypted with different public keys,are the same or not without decryption.Since peopl...Identity-based encryption with equality test(IBEET)is proposed to check whether the underlying messages of ciphertexts,even those encrypted with different public keys,are the same or not without decryption.Since people prefer to encrypt before outsourcing their data for privacy protection nowadays,the research of IBEET on cloud computing applications naturally attracts attention.However,we claim that the existing IBEET schemes suffer from the illegal trapdoor sharing problem caused by the inherited key escrow problem of the Identity-Based Encryption(IBE)mechanism.In traditional IBEET,the private key generator(PKG)with the master secret key generates trapdoors for all authorized cloud servers.Considering the reality in practice,the PKG is usually not fully trusted.In this case,the Private-Key Generator(PKG)may generate,share,or even sell any trapdoor without any risk of being caught,or not being held accountable,which may lead to serious consequences such as the illegal sharing of a gene bank's trapdoors.In this paper,to relieve the illegal trapdoor sharing problem in IBEET,we present a new notion,called IBEET Supporting Accountable Authorization(IBEET-AA).In IBEET-AA,if there is a disputed trapdoor,the generator will be distinguished among the PKG and suspected testers by an additional tracing algorithm.For the additional tracing function,except for the traditional indistinguishability(IND)and one-way(OW)security models in IBEET,we define three more security models to protect the tracing security against dishonest authorizers,PKG,and testers,respectively.Based on Gentry's IBE scheme,we instantiate IBEET-AA and give a specific construction along with a formalized security proof with random oracles.展开更多
As a future energy system,the smart grid is designed to improve the efficiency of traditional power systems while providing more stable and reliable services.However,this efficient and reliable service relies on colle...As a future energy system,the smart grid is designed to improve the efficiency of traditional power systems while providing more stable and reliable services.However,this efficient and reliable service relies on collecting and analyzing users’electricity consumption data frequently,which induces various security and privacy threats.To address these challenges,we propose a double-blockchain assisted secure and anonymous data aggregation scheme for fog-enabled smart grid named DA-SADA.Specifically,we design a three-tier architecture-based data aggregation framework by integrating fog computing and the blockchain,which provides strong support for achieving efficient and secure data collection in smart grids.Subsequently,we develop a secure and anonymous data aggregation mechanism with low computational overhead by jointly leveraging the Paillier encryption,batch aggregation signature and anonymous authentication.In particular,the system achieves fine-grained data aggregation and provides effective support for power dispatching and price adjustment by the designed double-blockchain and two-level data aggregation.Finally,the superiority of the proposed scheme is illustrated by a series of security and computation cost analyses.展开更多
According to the relation of an attribute set and its subset,the author presents a hierarchical attribute-based encryption scheme in which a secret key is associated with an attribute set.A user can delegate the priva...According to the relation of an attribute set and its subset,the author presents a hierarchical attribute-based encryption scheme in which a secret key is associated with an attribute set.A user can delegate the private key corresponding to any subset of an attribute set while he has the private key corresponding to the attribute set.Moreover,the size of the ciphertext is constant,but the size of private key is linear with the order of the attribute set in the hierarchical attribute-based encryption scheme.Lastly,we can also prove that this encryption scheme meets the security of IND-sSETCPA in the standard model.展开更多
The decryption participant＇s private key share for decryption is delegated by key generation center in the threshold IBE scheme.However,a key generation center which is absolutely trustworthy does not exist.So the au...The decryption participant＇s private key share for decryption is delegated by key generation center in the threshold IBE scheme.However,a key generation center which is absolutely trustworthy does not exist.So the author presents a certificateless threshold public key encryption scheme.Collaborating with an administrator,the decryption participant generates his whole private key share for decryption in the scheme.The administrator does not know the decryption participant＇s private key share for decryption.Making use of q-SDH assumption,the author constructs a certificateless threshold public key encryption scheme.The security of the scheme is eventually reduced to the solving of Decisional Bilinear Diffie-Hellman problem.Moreover,the scheme is secure under the chosen ciphertext attack in the standard model.展开更多
In this paper, an efficient hybrid proxy re-encryption scheme that allows the transformation of the ciphertexts in a traditional public key cryptosystem into the ciphertexts in an identity-based system is proposed. Th...In this paper, an efficient hybrid proxy re-encryption scheme that allows the transformation of the ciphertexts in a traditional public key cryptosystem into the ciphertexts in an identity-based system is proposed. The scheme is non-interactive, unidirectional and collude ＂safe＂. Furthermore, it is compatible with current IBE （identity-based encryption） deployments. The scheme has chosen ciphertext security in the random oracle model assuming the hardness of the Decisional Bilinear Diffie-Hellman problem.展开更多
This paper proposed an identity-based steganographic scheme, where a receiver with certain authority can recover the secret message ready for him, but cannot detect the existence of other secret messages. The proposed...This paper proposed an identity-based steganographic scheme, where a receiver with certain authority can recover the secret message ready for him, but cannot detect the existence of other secret messages. The proposed scheme created several separate covert communication channels tagged by the Fuzzy Identity-Based Encryption (FIBE) in one grayscale image. Then each channel is used to embed one secret message by using any content-aware steganographic scheme. Receivers with different attributes can extract different messages corresponded. The Experiments illustrated the feasibility of this identity-based secret message extraction. Further, the proposed scheme presents high undetectability against steganalytic attack launched by receivers without corresponded attributes.展开更多
Network marketing is a trading technique that provides companies with the opportunity to increase sales.With the increasing number of Internet-based purchases,several threats are increasingly observed in this field,su...Network marketing is a trading technique that provides companies with the opportunity to increase sales.With the increasing number of Internet-based purchases,several threats are increasingly observed in this field,such as user privacy violations,company owner(CO)fraud,the changing of sold products’information,and the scalability of selling networks.This study presents the concept of a blockchain-based market called ACR-MLM that functions based on the multi-level marketing(MLM)model,through which registered users receive anonymous and confidential rewards for their own and their subgroups’sales.Applying a public blockchain as the ACR-MLM framework’s infrastructure solves existing problems in MLM-based markets,such as CO fraud(against the government or its users),user privacy violations(obtaining their real names or subgroup users),and scalability(when vast numbers of users have been registered).To provide confidentiality and scalability to the ACR-MLM framework,hierarchical identity-based encryption(HIBE)was applied with a functional encryption(FE)scheme.Finally,the security of ACR-MLM is analyzed using the random oracle(RO)model and then evaluated.展开更多
文摘In ACM'CCS 2009,Camenisch,et al.proposed the Oblivious Transfer with Access Control(AC-OT) in which each item is associated with an attribute set and can only be available,on request,to the users who have all the attributes in the associated set.Namely,AC-OT achieves access control policy for conjunction of attributes.Essentially,the functionality of AC-OT is equivalent to the sim-plified version that we call AC-OT-SV:for each item,one attribute is associated with it,and it is requested that only the users who possess the associated attribute can obtain the item by queries.On one hand,AC-OT-SV is a special case of AC-OT when there is just one associated attribute with each item.On the other hand,any AC-OT can be realized by an AC-OT-SV.In this paper,we first present a concrete AC-OT-SV protocol which is proved to be secure in the model defined by Camenisch,et al..Then from the protocol,interestingly,a concrete Identity-Based Encryption(IBE) with Anonymous Key Issuing(AKI) is given which is just a direct application to AC-OT-SV.By comparison,we show that the AKI protocol we present is more efficient in communications than that proposed by Chow.
基金Rising-Star Program of Shanghai 2023 Science and Technology Innovation Action Plan(Yangfan Special Project),China(No.23YF1401000)Fundamental Research Funds for the Central Universities,China(No.2232022D-25)。
文摘The theory of quadratic residues plays an important role in cryptography.In 2001,Cocks developed an identity-based encryption(IBE)scheme based on quadratic residues,resolving Shamir’s 17-year-old open problem.However,a notable drawback of Cocks’scheme is the significant expansion of the ciphertext,and some of its limitations have been addressed in subsequent research.Recently,Cotan and Teşeleanu highlighted that previous studies on Cocks’scheme relied on a trial-and-error method based on Jacobi symbols to generate the necessary parameters for the encryption process.They enhanced the encryption speed of Cocks’scheme by eliminating this trialand-error method.Based on security analysis,this study concludes that the security of Cotan-Teşeleanu’s proposal cannot be directly derived from the security of the original Cocks’scheme.Furthermore,by adopting the Cotan-Teşeleanu method and introducing an additional variable as a public element,this study develops a similar enhancement scheme that not only accelerates the encryption speed but also provides security equivalent to the original Cocks’scheme.
文摘Attribute-based encryption(ABE)is a cryptographic framework that provides flexible access control by allowing encryption based on user attributes.ABE is widely applied in cloud storage,file sharing,e-Health,and digital rightsmanagement.ABE schemes rely on hard cryptographic assumptions such as pairings and others(pairingfree)to ensure their security against external and internal attacks.Internal attacks are carried out by authorized users who misuse their access to compromise security with potentially malicious intent.One common internal attack is the attribute collusion attack,in which users with different attribute keys collaborate to decrypt data they could not individually access.This paper focuses on the ciphertext-policy ABE(CP-ABE),a type of ABE where ciphertexts are produced with access policies.Our firstwork is to carry out the attribute collusion attack against several existing pairingfree CP-ABE schemes.As a main contribution,we introduce a novel attack,termed the anonymous key-leakage attack,concerning the context in which users could anonymously publish their secret keys associated with certain attributes on public platforms without the risk of detection.This kind of internal attack has not been defined or investigated in the literature.We then show that several prominent pairing-based CP-ABE schemes are vulnerable to this attack.We believe that this work will contribute to helping the community evaluate suitable CP-ABE schemes for secure deployment in real-life applications.
基金the National Natural Science Foundation of China (Nos. 60673072, 60803149)the National Basic Research Program (973) of China(No. 2007CB311201)
文摘This paper describes two identity-based broadcast encryption （IBBE） schemes for mobile ad hoc networks. The first scheme proposed achieves sub-linear size cipertexts and the second scheme achieves O（1）- size ciphertexts. Furthermore, when the public keys are transmitted, the two schemes have short transmissions and achieve O（1） user storage cost, which are important for a mobile ad hoc network. Finally, the proposed schemes are provable security under the decision generalized bilinear Diffi-Hellman （GBDH） assumption in the random oracles model.
文摘An identity-based encryption(IBE) was studied with non-interactively opening property that the plain text of a ciphertext can be revealed without affecting the security of the encryption system.Two kinds of non-interactive opening properties for IBE schemes were defined along with a concrete scheme in each case.
基金supported by the Nature Science Foundation of China under grant 60970119, 60803149the National Basic Research Program of China(973) under grant 2007CB311201
文摘In this paper,we show how to use the dual techniques in the subgroups to give a secure identity-based broadcast encryption(IBBE) scheme with constant-size ciphertexts. Our scheme achieves the full security(adaptive security) under three static(i.e. non q-based) assumptions. It is worth noting that only recently Waters gives a short ciphertext broadcast encryption system that is even adaptively secure under the simple assumptions. One feature of our methodology is that it is relatively simple to leverage our techniques to get adaptive security.
基金the National Natural Science Foundation of China(Nos.60673077,60873229)
文摘This paper proposes an identity-based encryption scheme with the help of bilinear pairings, where the identity information of a user functions as the user＇s public key. The advantage of an identity-based public key system is that it can avoid public key certificates and certificate management. Our identity-based encryption scheme enjoys short ciphertexts and provable security against chosen-ciphertext attack （CCA）.
文摘Broadcast encryption (BE) allows a sender to broadcast its message to a set of receivers in a single ciphertext. However, in broadcast encryption scheme, ciphertext length is always related to the size of the receiver set. Thus, how to improve the communication of broadcast encryption is a big issue. In this paper, we proposed an identity-based homomorphic broadcast encryption scheme which supports an external entity to directly calculate ciphertexts and get a new ciphertext which is the corresponding result of the operation on plaintexts without decrypting them. The correctness and security proofs of our scheme were formally proved. Finally, we implemented our scheme in a simulation environment and the experiment results showed that our scheme is efficient for practical applications.
文摘Identity-Based Encryption (IBE) has seen limited adoption, largely due to the absolute trust that must be placed in the private key generator (PKG)—an authority that computes the private keys for all the users in the environment. Several constructions have been proposed to reduce the trust required in the PKG (and thus preserve the privacy of users), but these have generally relied on unrealistic assumptions regarding non-collusion between various entities in the system. Unfortunately, these constructions have not significantly improved IBE adoption rates in real-world environments. In this paper, we present a construction that reduces trust in the PKG without unrealistic non-collusion assumptions. We achieve this by incorporating a novel combination of digital credential technology and bilinear maps, and making use of multiple randomly-chosen entities to complete certain tasks. The main result and primary contribution of this paper are a thorough security analysis of this proposed construction, examining the various entity types, attacker models, and collusion opportunities in this environment. We show that this construction can prevent, or at least mitigate, all considered attacks. We conclude that our construction appears to be effective in preserving user privacy and we hope that this construction and its security analysis will encourage greater use of IBE in real-world environments.
文摘A recent proposal by Adams integrates the digital credentials (DC) technology of Brands with the identity-based encryption (IBE) technology of Boneh and Franklin to create an IBE scheme that demonstrably enhances privacy for users. We refer to this scheme as a privacy-preserving identity-based encryption (PP-IBE) construction. In this paper, we discuss the concrete implementation considerations for PP-IBE and provide a detailed instantiation (based on q-torsion groups in supersingular elliptic curves) that may be useful both for proof-of-concept purposes and for pedagogical purposes.
基金supported by the National Natural Science Foundation of China under Grant Nos.62102299,62272362,62002288the Henan Key Laboratory of Network Cryptography Technology under Grant No.LNCT2022-A05,and the Youth Innovation Team of Shaanxi Universities.
文摘Identity-based encryption with equality test(IBEET)is proposed to check whether the underlying messages of ciphertexts,even those encrypted with different public keys,are the same or not without decryption.Since people prefer to encrypt before outsourcing their data for privacy protection nowadays,the research of IBEET on cloud computing applications naturally attracts attention.However,we claim that the existing IBEET schemes suffer from the illegal trapdoor sharing problem caused by the inherited key escrow problem of the Identity-Based Encryption(IBE)mechanism.In traditional IBEET,the private key generator(PKG)with the master secret key generates trapdoors for all authorized cloud servers.Considering the reality in practice,the PKG is usually not fully trusted.In this case,the Private-Key Generator(PKG)may generate,share,or even sell any trapdoor without any risk of being caught,or not being held accountable,which may lead to serious consequences such as the illegal sharing of a gene bank's trapdoors.In this paper,to relieve the illegal trapdoor sharing problem in IBEET,we present a new notion,called IBEET Supporting Accountable Authorization(IBEET-AA).In IBEET-AA,if there is a disputed trapdoor,the generator will be distinguished among the PKG and suspected testers by an additional tracing algorithm.For the additional tracing function,except for the traditional indistinguishability(IND)and one-way(OW)security models in IBEET,we define three more security models to protect the tracing security against dishonest authorizers,PKG,and testers,respectively.Based on Gentry's IBE scheme,we instantiate IBEET-AA and give a specific construction along with a formalized security proof with random oracles.
基金the National Natural Science Foundation of China(61971235,61871412,and 61771258)the Six Talented Eminence Foundation of Jiangsu Province(XYDXXJS-044)+4 种基金the China Postdoctoral Science Foundation(2018M630590)the 333 High-level Talents Training Project of Jiangsu Province,the 1311 Talents Plan of Nanjing University of Posts and Telecommunications(NUPT)the Open Research Fund of Jiangsu Engineering Research Center of Communication and Network Technology,NUPT(JSGCZX17011)the Scientific Research Foundation of NUPT(NY218058)the Open Research Fund of Anhui Provincial Key Laboratory of Network and Information Security(AHNIS2020001).
文摘As a future energy system,the smart grid is designed to improve the efficiency of traditional power systems while providing more stable and reliable services.However,this efficient and reliable service relies on collecting and analyzing users’electricity consumption data frequently,which induces various security and privacy threats.To address these challenges,we propose a double-blockchain assisted secure and anonymous data aggregation scheme for fog-enabled smart grid named DA-SADA.Specifically,we design a three-tier architecture-based data aggregation framework by integrating fog computing and the blockchain,which provides strong support for achieving efficient and secure data collection in smart grids.Subsequently,we develop a secure and anonymous data aggregation mechanism with low computational overhead by jointly leveraging the Paillier encryption,batch aggregation signature and anonymous authentication.In particular,the system achieves fine-grained data aggregation and provides effective support for power dispatching and price adjustment by the designed double-blockchain and two-level data aggregation.Finally,the superiority of the proposed scheme is illustrated by a series of security and computation cost analyses.
基金Supported by the National Natural Science Foundation of China(60903175,60703048)the Natural Science Foundation of Hubei Province(2009CBD307,2008CDB352)
文摘According to the relation of an attribute set and its subset,the author presents a hierarchical attribute-based encryption scheme in which a secret key is associated with an attribute set.A user can delegate the private key corresponding to any subset of an attribute set while he has the private key corresponding to the attribute set.Moreover,the size of the ciphertext is constant,but the size of private key is linear with the order of the attribute set in the hierarchical attribute-based encryption scheme.Lastly,we can also prove that this encryption scheme meets the security of IND-sSETCPA in the standard model.
基金Supported by the National Natural Science Foundation of China(60903175,60703048)the Natural Science Foundation of Hubei Province (2009CBD307,2008CDB352)
文摘The decryption participant＇s private key share for decryption is delegated by key generation center in the threshold IBE scheme.However,a key generation center which is absolutely trustworthy does not exist.So the author presents a certificateless threshold public key encryption scheme.Collaborating with an administrator,the decryption participant generates his whole private key share for decryption in the scheme.The administrator does not know the decryption participant＇s private key share for decryption.Making use of q-SDH assumption,the author constructs a certificateless threshold public key encryption scheme.The security of the scheme is eventually reduced to the solving of Decisional Bilinear Diffie-Hellman problem.Moreover,the scheme is secure under the chosen ciphertext attack in the standard model.
基金Supported by the National Natural Science Foundation of China (60673070)the Natural Science Foundation of Jiangsu Province, China (BK2006217)
文摘In this paper, an efficient hybrid proxy re-encryption scheme that allows the transformation of the ciphertexts in a traditional public key cryptosystem into the ciphertexts in an identity-based system is proposed. The scheme is non-interactive, unidirectional and collude ＂safe＂. Furthermore, it is compatible with current IBE （identity-based encryption） deployments. The scheme has chosen ciphertext security in the random oracle model assuming the hardness of the Decisional Bilinear Diffie-Hellman problem.
文摘This paper proposed an identity-based steganographic scheme, where a receiver with certain authority can recover the secret message ready for him, but cannot detect the existence of other secret messages. The proposed scheme created several separate covert communication channels tagged by the Fuzzy Identity-Based Encryption (FIBE) in one grayscale image. Then each channel is used to embed one secret message by using any content-aware steganographic scheme. Receivers with different attributes can extract different messages corresponded. The Experiments illustrated the feasibility of this identity-based secret message extraction. Further, the proposed scheme presents high undetectability against steganalytic attack launched by receivers without corresponded attributes.
文摘Network marketing is a trading technique that provides companies with the opportunity to increase sales.With the increasing number of Internet-based purchases,several threats are increasingly observed in this field,such as user privacy violations,company owner(CO)fraud,the changing of sold products’information,and the scalability of selling networks.This study presents the concept of a blockchain-based market called ACR-MLM that functions based on the multi-level marketing(MLM)model,through which registered users receive anonymous and confidential rewards for their own and their subgroups’sales.Applying a public blockchain as the ACR-MLM framework’s infrastructure solves existing problems in MLM-based markets,such as CO fraud(against the government or its users),user privacy violations(obtaining their real names or subgroup users),and scalability(when vast numbers of users have been registered).To provide confidentiality and scalability to the ACR-MLM framework,hierarchical identity-based encryption(HIBE)was applied with a functional encryption(FE)scheme.Finally,the security of ACR-MLM is analyzed using the random oracle(RO)model and then evaluated.
