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On the multiple use of quantum keysстатья
Дата последнего поиска статьи во внешних источниках: 1 апреля 2026 г.
- Авторы: Molotkov S.N., Sushchev I.S.
- Журнал: Laser Physics Letters
- Том: 23
- Номер: 3
- Год издания: 2026
- Издательство: Wiley - VCH Verlag GmbH & CO. KGaA
- Местоположение издательства: Germany
- Первая страница: 035208
- Последняя страница: 035208
- DOI: 10.1088/1612-202x/ae4f89
- Аннотация: In practice today, quantum keys are often reused because of practical limitations. It is clear that reusing a key weakens security compared to one-time-pad encryption, where perfect secrecy is achieved. For this reason, it is important to understand how the effort needed to find the key changes when the key is reused. We use the trace distance between two quantum states as a measure of closeness. Its maximum value is one, which means the two states are as different as possible. With simple arguments, we show that the trace distance is bounded above by several terms that capture (i) non-ideal quantum keys, (ii) plaintext redundancy, (iii) the number of key reuses, and (iv) the number of collisions of the block cipher. The trace distance approaches one exponentially fast with plaintext redundancy and with the number of key reuses; this means brute-force search becomes as easy as possible. For a random block cipher, the expected trace distance grows linearly with the number of key uses, with coefficient e−1 (e is Euler’s constant). The result is information-theoretic in nature.
- Добавил в систему: Сущев Иван Сергеевич