WEIGHTED ALGORITHM FOR FINGERPRINTING RELATIONAL DATABASES

The necessity and the feasibility of introducing attribute weight into digital fingerprinting system are given. The weighted algorithm for fingerprinting relational databases of traitor tracing is proposed. Higher weights are assigned to more significant attributes, so important attributes are more frequently fingerprinted than other ones. Finally, the robustness of the proposed algorithm, such as performance against collusion attacks, is analyzed. Experimental results prove the superiority of the algorithm.

An Improved Traitor Tracing Scheme Based on Bilinear Map

T6 et al presented a bilinear-map-based traitor tracing scheme（TSZ scheme） with revocation, but it is a symmetric scheme because it does not provide non-repudiation. In this paper, an improved TSZ scheme was proposed by using oblivious polynomial evaluation （OPE） protocol and service parameters. Under the recondition of general sameness capabilities of both TSZ and improved TSZ scheme, the new scheme adds some advantages such as providing multi-service capability, user＇s non-repudiation and data provider＇s no-framing innocent users. Furthermore, it is also proved to be semantically secure under the decisional bilinear Diffie-Hellman （DBDH problem） assumption.

New scheme of dynamic traitor tracing against the immediate rebroadcast attack

Traitor tracing schemes are introduced to combat the piracy scenarios. The notation of dynamic traitor tracing is proposed by Fiat and Tassa, which fights against rebroadcast of decrypted content. In this paper, using the idea of searching user address level by level, a new dynamic traitor tracing scheme based on a multilevel structure of user set is constructed. The scheme proposed can efficiently combat with the immediate rebroadcast attack, and possesses lower tracing complexity. Importantly, the tracing scheme can be applicable to systems with different sizes of subscriber sets.

Anonymous and Unlinkable Membership Authentication with Illegal Privilege Transfer Detection

Anonymous authentication schemes, mostly based on the notion of group signatures, allow a group member to obtain membership from a server and gain access rights if the member can prove their authenticity to the verifier. However, existing authentication schemes are impractical because they neglect to provide an exclusive verification of the blacklist. In addition, the schemes are unaware of malicious members who are involved in privilege transferring. In this paper, a novel membership authentication scheme providing detection of membership transfer and proof of membership exclusiveness to the blacklist is proposed.

Efficient Watermarking Scheme for Traitor Tracing Encryption Schemes

In the content distribution services,traitor tracing encryption schemes are useful tools to trace illegal users that distribute content illegally to unauthorized users.However,solo use of these schemes does not necessarily work well and has vulnerability.To complement the property of the traitor tracing schemes,it is effective to use watermarking scheme with them and the watermarking schemes with light load are required.A number of video watermarking methods with light load have been proposed that embed information into compressed video streams.When the compression scheme is MPEG2-Video,its codes are mostly pre-defined using coding tables,and therefore,information can be embedded in the compressed stream by substituting some of the codes.On the other hand,HEVC/H.265 uses arithmetic coding(CABAC)and it is not easy to substitute one code for another in a stream.To deal with this problem,a watermarking scheme for HEVC/H.265 video streams is proposed.It embeds information while the video is being encoded.A broadcasting system incorporating the scheme is also proposed.

RCDS:a right-confirmable data-sharing model based on symbol mapping coding and blockchain

The problem of data right confirmation is a long-term bottleneck in data sharing.Existing methods for confirming data rights lack credibility owing to poor supervision,and work only with specific data types because of their technical limitations.The emergence of blockchain is followed by some new data-sharing models that may provide improved data security.However,few of these models perform well enough in confirming data rights because the data access could not be fully under the control of the blockchain facility.In view of this,we propose a right-confirmable data-sharing model named RCDS that features symbol mapping coding(SMC)and blockchain.With SMC,each party encodes its digital identity into the byte sequence of the shared data by generating a unique symbol mapping table,whereby declaration of data rights can be content-independent for any type and any volume of data.With blockchain,all data-sharing participants jointly supervise the delivery and the access to shared data,so that granting of data rights can be openly verified.The evaluation results show that RCDS is effective and practical in data-sharing applications that are conscientious about data right confirmation.

Broadcast encryption schemes based on RSA

Three broadcast schemes for small receiver set using the property of RSA modulus are presented. They can solve the problem of data redundancy when the size of receiver set is small. In the proposed schemes, the center uses one key to encrypt the message and can revoke authorization conveniently. Every authorized user only needs to store one decryption key of a constant size. Among these three schemes, the first one has indistinguishability against adaptive chosen ciphertext attack （IND-CCA2） secure, and any collusion of authorized users cannot produce a new decryption key but the sizes of encryption modulus and ciphertext are linear in the number of receivers. In the second scheme, the size of ciphertext is half of the first one and any two authorized users can produce a new decryption key, but the center can identify them using the traitor tracing algorithm. The third one is the most efficient but the center cannot identify the traitors exactly.

Pirate decoder for the broadcast encryption schemes from Crypto 2005

In Crypto＇05, Boneh et al. presented two broadcast encryption schemes. Their work has exciting achievements： the header （also called ciphertexts） and the private keys are of constant size. In their paper, they give an open question to construct a traitor tracing algorithm for their broadcast encryption schemes, and combine the two systems to obtain an efficient trace-and-revoke system. In this paper, we give a negative answer to their open question. More precisely, we show that three or more insider users are able to collude to forge a valid private key for pirate decoding against their schemes. Moreover, we prove that there exists no traitor tracing algorithm to identify the colluders. Our pirate decoding can also similarly be applied to Lee et al.＇s broadcast encryption schemes in ISPEC＇06.

Efficient Broadcast Encryption Scheme Based on Number Theory Research Unit

In this paper, a new broadcast encryption scheme is proposed by using the efficient and computationally inexpensive public key cryptosystem NTRU （number theory research unit）. In our scheme, we use the idea of RSA and develop this idea from two-party to multi-party, and combine this multi-party public key idea with the multiplication in ring R of NTRU. What we get from this design is extremely efficient encryption and decryption, fast and easy key creation, low memory requirements and revocation property, etc. Moreover, this novel work contains other desirable features, such as traitor tracing. With its complexity only O（log2n）, the tracing algorithm of this system is more efficient than that of the previous ones.

A Multi-Key Pirate Decoder Against Traitor Tracing Schemes

In this paper we introduce an architecture for a multi-key pirate decoder which employs decryption keys from multiple traitors. The decoder has built-in monitoring and self protection functionalities and is capable of defeating most multiple-round based traitor tracing schemes such as the schemes based on the black-box confirmation method. In particular, the proposed pirate decoder is customized to defeat the private key and the public key fully collusion resistant traitor tracing （FTT） schemes, respectively. We show how the decoder prolongs a trace process so that the tracer has to give up his effort. FTT schemes are designed to identify all the traitors. We show that decoder enables the FTT schemes to identify at most 1 traitors. Finally, assuming the decoder is embedded with several bytes of memory, we demonstrate how the decoder is able to frame innocent users at will.