Private Database Queries Using Quantam States with Limited Coherence Times

Zhang, Li ; Hogg, Tad

HP Development Company

关键词: quantam information;    privacy;    digital property rights;   

RP-ID  :  HPL-2013-86

学科分类：计算机科学（综合）

美国|英语

来源: HP Labs

【 摘 要 】

We describe a method for private database queries using exchange of quantum states with bits encoded in mutually incompatible bases. For technology with limited coherence time, the database vendor can announce the encoding after a suitable delay to allow the user to privately learn one of two items in the database without the ability to also definitely infer the second item. This quantum approach also allows the user to choose to learn other functions of the items, such as the exclusive-or of their bits, but not to gain more information than equivalent to learning one item, on average. This method is especially useful for items consisting of a few bits by avoiding the substantial overhead of conventional cryptographic approaches.