At the moment I am doing a course about Bitcoin. The topic of the last session was the block-withholding attack and the course (being from 2014) claimed that there are no known attacks so far.

Is block-withholding a strategy used by mining pools in 2021? If so, where can I find evidence to back that up?

2 Answers 2


According to this article from 2016 it seems Slush pool had noticed or someone reported issues related to block withholding: http://organofcorti.blogspot.com/2016/02/detecting-unintentional-block.html

Not sure if it works in 2021 and which mining pools are affected.

While researching about OP_CTV I read about trustless coordination free mining pools: https://utxos.org/uses/miningpools/ so we can assume OP_CTV fixes this however it's not activated yet.

This type of mining pool has no trusted operator and requires no coordination. This eliminates various types of mining pool attacks, such as block witholding.

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    Note that "block witholding" can refer to two completely different attacks: (1) a means for large mining pools to get a better than proportional share of the income or (2) a way for mining pool users to hurt the pool's income by reducing their income while still being paid out. I suspect OP is asking about (1). Your article linked to is about (2). I'm not sure about the CTV one. Commented Jun 28, 2021 at 15:13
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    Yeah, the former was originally referred to as selfish-mining, the latter as "block solution withholding" or just "block withholding". Since then, a bunch of academic papers have used "block withholding" to refer to selfish mining, though, so I guess that distinction is no longer tangible.
    – Murch
    Commented Jun 28, 2021 at 16:32
  • Thanks @PieterWuille learnt something new. Will wait for OP to respond and reading more about "block withholding".
    – user103136
    Commented Jul 1, 2021 at 2:05

I found a lot of papers about block with holding attacks

This seems a survey https://www.researchgate.net/publication/309628092_Bitcoin_Block_Withholding_Attack_Analysis_and_Mitigation

These r newer https://www.researchgate.net/publication/343236094_Countering_Block_Withholding_Attack_Efficiently




Reading the abstracts this includes some of the Selfish Mining ways (I'm sure I read the idea in the IEEE paper in a Selfish Mining paper: Detective Mining: Selfish Mining Becomes Unrealistic under Mining Pool Environment, Suhyeon Lee and Seungjoo Kim, CIST(Center for Information Security Technologies), Korea University, Korea; ADD(Agency for Defense Development), Korea.) I don't think Selfish Mining or Block With Holding is something u'll read in the news about, it is a miner or a pool used a block mining efforts; only maybe if it helped in a 51% attack which the papers point as a risk.

Wait, I did find more in my library under Selfish Mining https://academy.binance.com/en/articles/selfish-mining-explained https://outlast.me/selfish-mining-in-five-tweets/ In this one there's a curve unfortunately I don't know its source about ratio of Selfish Mining in known pools enter image description here

[I added this part for the sake of promoting knowledge, understanding, scientific research,... nothing more]

I also wondered would it be a malicious way to do front running?ie convince a high bidder ( would be paid more to get his TX as fast as possible) that his/her TX is guaranteed say 1st place in ur block, while u plan to drop the whole block & front run with another TX (maybe I did read that in a paper before, MEV ?) & yes I did read about it under MEV, they're called Privately Mined Transactions or Private Transactions , they didn't allow more links so I'll just add the screenshots I made about it ( u can search for urself under these terms)

enter image description here enter image description here

  • 1
    The question asked for evidence that block-withholding (probably selfish mining) attacks have happened in practice. This answer lists a number of theoretical papers without addressing the question.
    – Murch
    Commented Jun 28, 2021 at 16:44

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