A Survey on Blockchain Technology and its
Security
Huaqun Guo
Institute for Infocomm Research, A*STAR, Singapore
guohuaqun@u.nus.edu
Xingjie Yu
*
Singapore
stefanie_yxj@hotmail.com
Abstract—Blockchain is a technology which has desirable
features of decentralization, autonomy, integrity, immutability,
verification, fault-tolerance, anonymity, auditability and
transparency. In this paper, we first carry out a deeper survey
about Blockchain technology, especially its history, consensus
algorithms’ quantitative comparisons, details of cryptography
in terms of public key cryptography, Zero-Knowledge Proofs
and hash functions used in the Blockchain, and the
comprehensive list of Blockchain applications. Further, the
security on Blockchain itself is a focus in this paper. In
particular, we assess the Blockchain security from risk analysis
to derive comprehensive Blockchain security risk categories,
analyze the real attacks and bugs against Blockchain, and
summarize the recently developed security measures on
Blockchain. Finally, the challenges and research trends are
presented to achieve more scalable and securer Blockchain
systems for the massive deployments.
Keywords-Blockchain; consensus algorithm; smart contract;
risk; Blockchain security
I.
I
NTRODUCTION
In Blockchain, data are kept in a distributed ledger. It is
the Blockchain technology to provide integrity and
availability that allows participants in the Blockchain network
to write, read and verify transactions recorded in a distributed
ledger. However, it does not allow the deletion and
modification operations on
the transactions and other
information stored on its ledger. The Blockchain system is
supported and secured by cryptographic primitives and
protocols, e.g., digital signature,
hash functions, etc. These
primitives guarantee the transactions that are recorded into the
ledger are integrity-protected, authenticity-verified, and non-
repudiated. Further, as a distributed network, to allow the
entire set of participants
to agree on a unified record, the
Blockchain technology further needs a consensus protocol,
which is essentially a set of rules to follow by every
