Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Authentication Without Identification using Anonymous Credential System   Privacy and security are often intertwined. For example, identity theft is
rampant because we have become accustomed to authentication by identification.
To obtain some service, we provide enough information about our identity for an
unscrupulous person to steal it (for example, we give our credit card number to
Amazon.com). One of the consequences is that many people avoid e-commerce
entirely due to privacy and security concerns. The solution is to perform
authentication without identification. In fact, all on-line actions should be
as anonymous as possible, for this is the only way to guarantee security for
the overall system. A credential system is a system in which users can obtain
credentials from organizations and demonstrate possession of these credentials.
Such a system is anonymous when transactions carried out by the same user
cannot be linked. An anonymous credential system is of significant practical
relevance because it is the best means of providing privacy for users.

15
The categories of this paper are: nucl-ex
0
The categories of this paper are: hep-ph
36
The categories of this paper are: cmp-lg
22
The categories of this paper are: chao-dyn
13
The categories of this paper are: quant-ph
21
The categories of this paper are: adap-org
2
The categories of this paper are: math
11
The categories of this paper are: hep-lat
28
The categories of this paper are: alg-geom
25
The categories of this paper are: patt-sol
30
The categories of this paper are: q-alg
5
The categories of this paper are: gr-qc
18
The categories of this paper are: econ
10
The categories of this paper are: q-bio
27
The categories of this paper are: comp-gas
4
The categories of this paper are: cond-mat