Suhyeon Lee

2026

1. 

   Inside Qubic’s Selfish Mining Campaign on Monero: Evidence, Tactics, and Limits

   Suhyeon Lee, and Hyeongyeong Kim

   In arXiv preprint arXiv:2512.01437, Feb 2026

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   We analyze Qubic’s advertised selfish mining campaign on Monero in 2025. Combining data from Monero nodes, and the Qubic pool API, we reconstruct Qubic-attributed blocks and hashrate and detect ten intervals consistent with selfish mining strategies. In these intervals, Qubic’s average hashrate share rises to the 23-34% range, yet sustained 51% control is never observed. We evaluate the campaign against the classical selfish mining model and a modified Markov-chain model that reflects Qubic’s conservative release strategy: both predict lower revenue than honest mining at the inferred parameters, and the data largely confirms this while still showing noticeable deviations from the predicted curve. We interpret this gap between model and measurements in terms of Qubic’s time-varying hashrate and coarse-grained attack segmentation.

2022

1. 

   Block Double-Submission Attack: Block Withholding Can Be Self-Destructive

   Suhyeon Lee, Donghwan Lee, and Seungjoo Kim

   In AFT 2022 - ACM Conference on Advances in Financial Technologies, Feb 2022

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   Proof-of-Work (PoW) is a Sybil control mechanism adopted in blockchain-based cryptocurrencies. It prevents the attempt of malicious actors to manipulate distributed ledgers. Bitcoin has successfully suppressed double-spending by accepting the longest PoW chain. Nevertheless, PoW encountered several major security issues surrounding mining competition. One of them is a Block WithHolding (BWH) attack that can exploit a widespread and cooperative environment called a mining pool. This attack takes advantage of untrustworthy relationships between mining pools and participating agents. Moreover, detecting or responding to attacks is challenging due to the nature of mining pools. In this paper, however, we suggest that BWH attacks also have a comparable trust problem. Because a BWH attacker cannot have complete control over BWH agents, they can betray the belonging mining pool and seek further benefits by trading with victims. We prove that this betrayal is not only valid in all attack parameters but also provides double benefits; finally, it is the best strategy for BWH agents. Furthermore, our study implies that BWH attacks may encounter self-destruction of their own revenue, contrary to their intention.

   @inproceedings{lee2022block,
     author = {Lee, Suhyeon and Lee, Donghwan and Kim, Seungjoo},
     title = {Block Double-Submission Attack: Block Withholding Can Be Self-Destructive},
     year = {2022},
     isbn = {9781450398619},
     publisher = {Association for Computing Machinery},
     address = {New York, NY, USA},
     doi = {10.1145/3558535.3559787},
     booktitle = {AFT 2022 - ACM Conference on Advances in Financial Technologies},
     pages = {232–243},
     numpages = {12},
     keywords = {blockchain, proof-of-work, block double-submission attack, block withholding attack, game theoretic analysis},
     location = {Cambridge, MA, USA},
     series = {AFT '22},
   }