Design And Implementation Of Threshold RSA Signature Scheme

With rapid development of the modern Information & Communications Technology and computer technology, especially the development of the internet, network security becomes a hotspot in IT filed to keep the survival and development of the internet. Although modern cryptography provides symmetric-key block ciphers, public-key encryption, digital signature and key exchange technology to guarantee the information safety, all those algorithms' safety only relies on a small scale key. Once the key is leaked, the whole system would collapse and lead to the encrypted files decrypted and maliciously sign illegal files with the key by hackers which results in serious consequences. So it becomes a key problem how to build a better security protection scheme and key management system by making use of the cryptography algorithm in practice.Then there are many outstanding key management technologies, such as the theory of secret trusteeship raised by American in 1993, X.509 standard established by International Organization of Standardization and Kerberos Protocol etc. Since 1979, Shamir presents the theory of secret sharing and threshold scheme, which promotes the development and practical application of this theory.Digital signature as an information safety technology plays an important role in protecting the integrity of the data, undeniability and verifiability of information. Combining the digital signature with the secret sharing technology leads to the birth of the threshold signature technology. And the (t, n) threshold signature means that only t or more participators can produce the signature.First, the thesis analyses the research background of threshold RSA signature technology and the evolvement of the theory in the world. After introducing basic knowledge of the cryptology, this thesis introduces the famous threshold RSA signature the Shoup's scheme, and summarizes the general problems in existing schemes. Then focus on introducing "A New RSA Threshold Group Signature Scheme Based on Modified Shamir's Secret Sharing Solution", analyzing them in respect of efficiency, and design a distributed trusted center based on the this scheme and the quantitative analysis result, improving the efficiency of distributing sub-kyes process. Then this thesis introduces "A Threshold Signature Scheme for Multiple Groups based on RSA" scheme used to provide the threshold signature function for multiple independent groups. Finally, this thesis introduces the threshold RSA signature system with a trusted center based on the the chosen scheme and the robust and efficient sharing of RSA functions, which designed and developed by the author with the OpenSSL library and VS2005 Integrated Development Environment.