Análise de segurança de criptografia quântica baseada em teletransporte

• Ano de defesa: 2021
• Autor(a) principal: Lima, Diogo Henrique Garcia
• Orientador(a): Rigolin, Gustavo Garcia
• Tipo de documento: Tese
• Tipo de acesso: Acesso aberto
• Idioma: por
• Instituição de defesa: Universidade Federal de São Carlos; Câmpus São Carlos
• Programa de Pós-Graduação: Programa de Pós-Graduação em Física - PPGF
• Palavras-chave em Português: Criptografia quântica; Teletransporte quântico; Comunicação quântica
• Palavras-chave em Inglês: Quantum cryptography; Quantum teleportation; Quantum communication
• Área do conhecimento CNPq: CIENCIAS EXATAS E DA TERRA::FISICA::FISICA GERAL::FISICA CLASSICA E FISICA QUANTICA; MECANICA E CAMPOS; CIENCIAS EXATAS E DA TERRA::FISICA::FISICA GERAL
• Link de acesso: https://repositorio.ufscar.br/handle/20.500.14289/14010

We prove that the teleportation based quantum cryptography protocol presented in [Opt. Commun. 283, 184 (2010)], which is built using only orthogonal states encoding the classical bits that are teleported from Alice to Bob, is asymptotically secure against all types of individual and collective attacks. We then investigate modifications to that protocol leading to greater secret-key rates and to security against coherent attacks. In other words, we show an unconditional secure quantum key distribution protocol that does not need non-orthogonal quantum states to encode the bits of the secret key sent from Alice to Bob. We also revisit the security proof of the BB84 protocol by exploring the non-uniqueness of the Schmidt decomposition of its entanglement-based representation. This allows us to arrive at a secure transmission of the key for a slightly greater quantum bit error rate (quantum communication channel’s noise) when compared to its standard security analysis. After that, we investigate how different types of the noise usually present in realistic implementations of the BB84 protocolo affect its operation.