  The current blockchain system for cryptocurrency exchanges primarily employs
elliptic curve cryptography (ECC) for generating key pairs in wallets, and
elliptic curve digital signature algorithms (ECDSA) for generating signatures
in transactions. Consequently, with the maturation of quantum computing
technology, the current blockchain system faces the risk of quantum computing
attacks. Quantum computers may potentially counterfeit signatures produced by
ECDSA. Therefore, this study analyzes the vulnerabilities of the current
blockchain system to quantum computing attacks and proposes a post-quantum
cryptography (PQC)-based blockchain system to enhance security by addressing
and improving each identified weakness. Furthermore, this study proposes
PQC-based wallets and PQC-based transactions, utilizing PQC digital signature
algorithms to generate PQC-based signatures for the inputs in PQC-based
transactions, thereby preventing signatures from being counterfeited by quantum
computing. Experimental results demonstrate that the efficiency of the
Dilithium algorithm, a PQC digital signature algorithm, in producing wallets,
generating signatures, and verifying signatures surpasses that of ECDSA in the
current blockchain system. Furthermore, the Dilithium algorithm also exhibits a
higher security level.
