Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: HyperLogLog (HLL) Security: Inflating Cardinality Estimates   Counting the number of distinct elements on a set is needed in many
applications, for example to track the number of unique users in Internet
services or the number of distinct flows on a network. In many cases, an
estimate rather than the exact value is sufficient and thus many algorithms for
cardinality estimation that significantly reduce the memory and computation
requirements have been proposed. Among them, Hyperloglog has been widely
adopted in both software and hardware implementations. The security of
Hyperloglog has been recently studied showing that an attacker can create a set
of elements that produces a cardinality estimate that is much smaller than the
real cardinality of the set. This set can be used for example to evade
detection systems that use Hyperloglog. In this paper, the security of
Hyperloglog is considered from the opposite angle: the attacker wants to create
a small set that when inserted on the Hyperloglog produces a large cardinality
estimate. This set can be used to trigger false alarms in detection systems
that use Hyperloglog but more interestingly, it can be potentially used to
inflate the visits to websites or the number of hits of online advertisements.
Our analysis shows that an attacker can create a set with a number of elements
equal to the number of registers used in the Hyperloglog implementation that
produces any arbitrary cardinality estimate. This has been validated in two
commercial implementations of Hyperloglog: Presto and Redis. Based on those
results, we also consider the protection of Hyperloglog against such an attack.

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The categories of this paper are: q-bio
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The categories of this paper are: cond-mat
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The categories of this paper are: mtrl-th
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The categories of this paper are: q-alg
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The categories of this paper are: q-fin
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The categories of this paper are: eess
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The categories of this paper are: dg-ga
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The categories of this paper are: plasm-ph
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The categories of this paper are: math
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The categories of this paper are: ao-sci
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The categories of this paper are: comp-gas
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The categories of this paper are: chao-dyn
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The categories of this paper are: econ
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The categories of this paper are: hep-lat
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The categories of this paper are: quant-ph
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The categories of this paper are: funct-an