This paper presents a practical method of quantum tomography for decoding the state of photons in a multistage cryptography protocol. This method works if the polarization angles are defined on a fixed plane, as is assumed in several quantum cryptography protocols. We show if there are 2 m polarization angles in a fixed plane, we need m number of filters… (More)
This paper describes how the communicating parties can employ intensity and state estimation to detect if the eavesdropper has siphoned off and injected photons in the received communication. This is of relevance in quantum cryptography based on random rotations of photon polarizations.
This paper presents noise analysis for the two-stage and the three-stage quantum cryptographic protocols based on random polarization rotations. The noise model used is that of uniform distribution of error over a certain small range that is associated with each link without regard for the source of the error. The noise in different links is taken to be… (More)
This paper investigates the effect of permutations on blocks of a prime reciprocal sequence on its randomness. A relationship between the number of permutations used and the improvement of performance is presented. This can be used as a method for increasing the cryptographic strength of pseudorandom sequences. Introduction Pseudorandom sequences that are… (More)