Secure Audio Teleconference
A number of alternative encryption techniques have been suggested for secure audio teleconferencing implementable on public switched network, in which the centralized facility, called bridge, does not hold any secret. The role of the bridge is to synchronously add simultaneous encrypted signals, modulo some known number, and then transmit the result to all the participants. Each terminal has a secret key, with which it can decrypt the above modular sum of encrypted signals to obtain the desired ordinary sum of cleartext signals. Secrecy of the systems is analyzed. Some of which are provably secure, assuming the existence of one way functions, and for the others we have partial cryptanalysis.
We also present a N-party identification and signature systems, based on Fiat and Shamir’s single party systems, and another N-party signature system based on discrete-log problem. Our system have communication complexity 2N times that of the basic Fiat-Shamir systems (as compared to a factor of N 2 in the direct application of the basic scheme to all pairs).
Key Wordssecrecy identification signature bridging
- [BY]E. Brickell and Y. Yacobi, “On Privacy Homomorphisms”, Eurocrypt-87Google Scholar
- [CH]D. Chaum, J. van de Graaf: “An Improved Protocol for Demonstrating Possession of a Discrete Logarithm and Some Generalizations”, Eurocrypt-87Google Scholar
- [FS]A. Fiat and A. Shamir:“How to prove yourself: Practical Solutions to Identification and Signature Problems”, to appear in Proc. Crypto-86.Google Scholar
- [KO]K. Koyama and K. Ohta:“Identity based conference key distribution systems”, to appear in Crypto-87.Google Scholar
- [RAD]Rivest, Adleman and Dertouzos:“ On data banks and privacy homomorphisms”, in Foundations of secure computation, edited by Demillo et al. Academic Press 1978.Google Scholar
- [Y]A.C. Yao, “Theory and Applications of Trapdoor Functions”, Proc. Foundations of Computer Science, 1982, pp.80–91.Google Scholar