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Research On Subliminal Channel Technique In Schnorr-Type Signatures

Posted on:2011-10-13Degree:MasterType:Thesis
Country:ChinaCandidate:Y H ZhangFull Text:PDF
GTID:2178360302491284Subject:Applied Mathematics
Abstract/Summary:PDF Full Text Request
Simmons utilized a"prisoners"model to illustrate the fact that the security protocol used by the United States to the verification system was flawed, thus the concept of the subliminal channel was formally introduced. A subliminal channel is a kind of covert channels constructed in the overt channel, by which secret information can be hidden in the output crypto-data of the probabilistic digital signatures and authentication algorithms. As an important application of the information hiding technology, the subliminal channels can be used for legitimate users to transmit secret information, and be widely used in military, e-commerce and other fields. However, the subliminal channels are characteristic of hiding a communication fact, so criminals and espionage agencies can use them to transmit information without being discovered. The subliminal channels present a deeper challenge to information security. As society begets an increasing demand for information security, it has become an urgent problem to be solved for security mechanisms to effectively close the subliminal channels.The main contributions of the dissertation are listed as follows.(1) A signature scheme of narrow-band subliminal channel is proposed based on the Schnorr digital signature. In addition, a real-time test of the signature is made. According to the test result, a more desirable method of transmitting subliminal information on some condition is put forward.(2) A new subliminal-free protocol is designed. It is shown that the protocol can completely close the subliminal channels existing in the random session keys in the Schnorr signature scheme. In the proposed scheme, the signature authority of the signer is guaranteed. Then the efficiency of the new scheme is analyzed.(3) A new interactive subliminal-free protocol is designed by the whole substitution. It is shown that the proposed protocol can completely close the subliminal channels existing in the random parameters in Schnorr-Type ordinal multi-signature schemes. To sign a given message, it is necessary for the warden to cooperate with all signers. In computational complexity and communications cost, the proposed protocol is more efficient than the existing schemes.(4) Subliminal channels in the EDL signature are constructed firstly, and then an interactive subliminal-free protocol is designed. It is shown that the proposed protocol can completely close the subliminal channels existing in the random parameters in the EDL signature. The proposed protocol is proved to be secure in RO(random oracle) model assuming the CDH(computational Diffie-Hellman) problem is hard.
Keywords/Search Tags:Cryptography, Digital signature, Information hiding, Subliminal channel, Real-Time test, Free protocol, Random oracle model
PDF Full Text Request
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