期刊名称：International Journal on Computer Science and Engineering
印刷版ISSN：2229-5631
电子版ISSN：0975-3397
出版年度：2012
卷号：4
期号：12
页码：1881-1889
出版社：Engg Journals Publications
摘要：Before a message is sent out, the sender of the message would sign it using a digital signature scheme and then encrypt the message (and the signature) use a private key encryption algorithm under a randomly chosen message encryption key. The random message encryption key would then be encrypted using the recipient's public key. We call this process two-step approach: �signature-then-encryption�. Concept signcryption, first proposed by Zheng, is a cryptography primitive which combines both the functions of digital signature and public key encryption in a logical single step, and with a computational cost and communication overhead are significantly lower than that needed by traditional signature then encryption. In Zheng�s scheme, the signature verification can be done recipient�s private key at receiver end and its security are based on mainly Discrete Logarithm Problem (DLP), reversing one way hash function. In proposed modified signcryption scheme, security is based on the intractability of three hard problems: Discrete Logarithm Problem, reversing one way hash function and to determine prime factors of a composit number. Proposed signcryption scheme has all the benefits of signcryption and is also able to resolve the dispute / problem of non repudiation by independent third party, without compromising with sender and recipient�s private keys.
关键词：RSA; ElGamal; Discrete logarithm problem (DLP) ;Cryptography; Secure communication; Digital Signature; Hash; Encryption; Decryption ; Signcryption.
