Title
Information Leakage due to Revealing Randomly Selected Bits
Abstract
This note describes an information theory problem that arose from some analysis of quantum key distribution protocols. The problem seems very natural and is very easy to state but has not to our knowledge been addressed before in the information theory literature: suppose that we have a random bit string y of length n and we reveal k bits at random positions, preserving the order but without revealing the positions, how much information about y is revealed? We show that while the cardinality of the set of compatible y strings depends only on n and k, the amount of leakage does depend on the exact revealed x string. We observe that the maximal leakage, measured as decrease in the Shannon entropy of the space of possible bit strings, corresponds to the x string being all zeros or all ones and that the minimum leakage corresponds to the alternating x strings. We derive a formula for the maximum leakage (minimal entropy) in terms of n and k. We discuss the relevance of other measures of information, in particular min-entropy, in a cryptographic context. Finally, we describe a simulation tool to explore these results.
Year
DOI
Venue
2015
10.1007/978-3-319-26096-9_33
Lecture Notes in Computer Science
Keywords
Field
DocType
Information leakage,Quantum key distribution,Entropy,Subsequence,Supersequence,Deletion channel,Simulation
Information theory,Quantum key distribution,Discrete mathematics,Information leakage,Leakage (electronics),Computer science,Computer security,Cardinality,Theoretical computer science,Deletion channel,Bit array,Entropy (information theory)
Conference
Volume
ISSN
Citations 
9379
0302-9743
1
PageRank 
References 
Authors
0.35
10
3
Name
Order
Citations
PageRank
Arash Atashpendar193.21
A. W. Roscoe23125.90
Peter Y. A. Ryan372866.96