Secure Storage for Identification; Random Resources and Privacy Leakage

Ahlswede and Dueck introduced identification via channels as a new paradigm in information theory. They showed that the number of messages that can reliably be identified over a noisy channel grows doubly exponentially with the block length. In this paper, we also consider identification, but we assume that messages are stored on a database such that they can be identified. In addition, the legitimate users have access to the output of a source. This source allows us to store messages securely. It is also used to increase the number of messages that can be stored securely on the database and identified reliably. We define a protocol for secure storage for identification such that the number of stored messages that can be identified grows doubly exponentially with the number of symbols read from the source and the number of storage cells available, respectively. We also consider the privacy leakage of the protocols used for identification. So, it makes sense to consider two sources. We assume one source is public, whereas the other source is available only to the legitimate users. The public source is used to increase the number of messages that can be identified, while the second source is used to guarantee secrecy. Using the public source does not increase the privacy leakage. So, we can possibly achieve a higher number of messages that can be identified, while the privacy leakage does not increase using two sources. As a by-product, we also get new results on common randomness generation.