Noised based cipher system

A computationally secure noised based cipher system is proposed. The advantage of this cipher system is that it operates above noise level. Therefore computationally secure communication can be done when error correction code fails. Another feature of this system is that minimum number of exhaustive key search can be made fixed.Comment: Revised, Latex, 4 page

Complete Entanglement-Based Communication With Security

If, due to some catastrophe, our classical communication system is destroyed but quantum entangled state survived, in that entanglement age, it is widely believed, the whole world would be communication less. It is discussed that complete entanglement based communication even with security is possible in that scenario. In this context, the notion of cheating-free Bell's inequality test is introduced.Comment: latex, 12 pages, Revise

Unconditionally secure quantum bit commitment is simply possible

Mayers, Lo and Chau proved unconditionally secure quantum bit commitment is impossible. It is shown that their proof is valid only for a particular model of quantum bit commitment encoding, in general it does not hold good. A different model of unconditionally secure quantum bit commitment - both entanglement and disentanglement-based - is presented. Even cheating can be legally proved with some legal evidences. Unconditionally secure quantum bit commitment can be established on the top of unconditionally secure quantum coin tossing, which is also claimed to be two-way impossible.Comment: Latex 14 pages, revised versio

Space-Time Encoding

It is widely believed that one signal can carry maximum one bit of information, and minimum KTlog2 energy is required to transmit or to erase a bit. Here it is shown four bits of information can be transmitted by one signal in four dimensional space-time. It implies space-time cannot be ignored to determine the minimal energy cost of information processing.Comment: Latex, 7 page

Entanglement versus disentanglement: Quantum Cryptography

In quantum information, the role of entanglement and disentanglement is itself a subject of research and debate. Earlier works on quantum cryptography have almost established that entanglement has no special advantage in quantum cryptography. In this paper we reveal that entanglement is better ingredient than disentanglement for our alternative quantum cryptography.Comment: Latex 8 pages, Revised versio

Quantum communication is possible with pure state

It is believed that quantum communication is not possible with a pure ensemble of states because quantum entropy of pure state is zero. This is indeed possible due to geometric consequence of entanglement

A simple unbreakable code

A simple unbreakable cipher system is presented which uses the concept of "pseudo-bits" that has never been used in either classical or quantum cryptography.Comment: Revised, 6 page

Entangled messages

It is sometimes necessary to send copies of the same email to different parties, but it is impossible to ensure that if one party reads the message the other parties will bound to read it. We propose an entanglement based scheme where if one party reads the message the other party will bound to read it simultaneously.Comment: PDF, 2 Page

Complete Quantum Communication with Security

The long-standing problem of quantum information processing is to remove the classical channel from quantum communication. Introducing a new information processing technique, it is discussed that both insecure and secure quantum communications are possible without the requirement of classical channel.Comment: Latex, 15 pages, Final Version, Typo error correcte

Perfectly secure cipher system

We present a perfectly secure cipher system based on the concept of fake bits which has never been used in either classical or quantum cryptography.Comment: Tex, 6 page