Ali Zaghian; Bagher Bagherpour
Abstract
A non-interactive (t,n)-publicly veri able secret sharing scheme (non-interactive (t,n)-PVSS scheme) is a (t,n)-secret sharing scheme in which anyone, not only the participants of the scheme, can verify the correctness of the produced shares without interacting with the dealer and participants. The (t,n)-PVSS ...
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A non-interactive (t,n)-publicly veri able secret sharing scheme (non-interactive (t,n)-PVSS scheme) is a (t,n)-secret sharing scheme in which anyone, not only the participants of the scheme, can verify the correctness of the produced shares without interacting with the dealer and participants. The (t,n)-PVSS schemes have found a lot of applications in cryptography because they are suitable for real-life scenarios in which an external verifier is required to check the correctness of the produced shares without interacting with the dealer and participants. In this paper, we propose a non-interactive (t,n)-PVSS scheme using the non-homogeneous linear recursions (NHLRs), and prove its security with a formal method. We compare the computational complexity of our scheme with that of Schoenmakers's scheme and show that our non-interactive (t,n)-PVSS scheme runs faster than Schoenmakers's scheme when n > 5 and n> t >(2n+9)/n. The communicational complexity of our scheme is almost equal to that of Schoenmakers's scheme.
R. Ramezanian
Abstract
In information security, ignorance is not bliss. It is always stated that hiding the protocols (let the other be ignorant about it) does not increase the security of organizations. However, there are cases that ignorance creates protocols. In this paper, we propose distributed contingency logic, a proper ...
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In information security, ignorance is not bliss. It is always stated that hiding the protocols (let the other be ignorant about it) does not increase the security of organizations. However, there are cases that ignorance creates protocols. In this paper, we propose distributed contingency logic, a proper extension of contingency (ignorance) logic. Intuitively, a formula is distributed contingent in a group of agent if and only if it does not follow from the knowledge of all individual agents put together. We formalize secret sharing scheme (a security property that is built upon ignorance of all agents), and a man in the middle attack to a weak protocol in our logic. We also illustrate a condition where disclose a secret may hide another one forever. Finally we prove the main theorems of every logic, soundness and completeness. We also prove that distributed contingency logic is more expressive than classical contingency logic and epistemic logic.