Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Blockchain-based Smart Contracts - Applications and Challenges   A blockchain-based smart contract or a "smart contract" for short, is a
computer program intended to digitally facilitate the negotiation or
contractual terms directly between users when certain conditions are met. With
the advance in blockchain technology, smart contracts are being used to serve a
wide range of purposes ranging from self-managed identities on public
blockchains to automating business collaboration on permissioned blockchains.
In this paper, we present a comprehensive survey of smart contracts with a
focus on existing applications and challenges they face.

2
The categories of this paper are: math
10
The categories of this paper are: q-bio
14
The categories of this paper are: math-ph
5
The categories of this paper are: gr-qc
23
The categories of this paper are: solv-int
17
The categories of this paper are: q-fin
16
The categories of this paper are: stat
29
The categories of this paper are: funct-an
25
The categories of this paper are: patt-sol
18
The categories of this paper are: econ
37
The categories of this paper are: supr-con
9
The categories of this paper are: nlin
7
The categories of this paper are: hep-th
30
The categories of this paper are: q-alg
15
The categories of this paper are: nucl-ex
36
The categories of this paper are: cmp-lg