الفهرس 
QUANTUM INFORMATIONOnly 14 pages are availabe for public view
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Abstract
Quantum information processing is a new and dynamic research field. It focuses on the consequences of encoding digital bits on quantum objects. Most importantly, it exploits the fact that, according to quantum physics principles, the mere observing of a quantum object perturbs it in an irreparable way. Thus, eavesDROPping over the communication channel can be easily detected.
Quantum cryptography solves the key distribution problem by allowing the exchange of a cryptographic key between two remote parties with absolute security, guaranteed by the laws
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of physics. Numerous protocols have been introduced in literature with the BB84 protocol
being the first and still widely used quantum key distribution protocol. However, if two parties are to establish a shared key by a classical or quantum key distribution protocol, they must affirm each other’s identities at first. In other words, they need an authentication mechanism.
In this thesis, a key distribution protocol based on the integration of both classical and quantum cryptography is developed. Quantum cryptography is used for secure optical transmission which employs quantum mechanisms to distribute session keys. Classical cryptography provides convenient techniques that enable efficient user authentication and prevent denial of previous commitments. The proposed scheme is based on the RSA-TBOS signcryption scheme to achieve the combined functionality of a digital signature and encryption in an efficient manner. The transmitter generates a random session key, and applies the signcryption module to it. It therefore offers three services: privacy, authenticity and non¬repudiation. The ciphertext is converted to binary bits then to qubits using a pre-shared random number between the transmitter and receiver. The session key is used later for secure transmission of messages over a public optical channel.
The proposed protocol has several advantages over other schemes in literature. The number of rounds and the number of keys stored per user are kept minimal promoting its use over large networks. Moreover, the integrity of the message containing the key can be verified through the use of a cryptographic hash function.