b10c

Bitcoin developer and observer

Public Key

npub1kyxqqqq8n2pu7f5pthr48zqcmr2k52vrud6wxzjpg0jsqcyhs3tshfc6vv

NIP-05 Address

Profile Code

nprofile1qqstzrqqqqre4q70y6q4m36n3qvd34t29xp7xa8rpfq58egqvztcg4cpp4mhxue69uhkummn9ekx7mqpzpmhxue69uhkummnw3ezuamfdejsm38mjm

Publishing to

nos.lol

nostr.wine

relay.damus.io

Author Public Key

npub1kyxqqqq8n2pu7f5pthr48zqcmr2k52vrud6wxzjpg0jsqcyhs3tshfc6vv

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Last Notes

2026-04-09 00:02:57 CEST

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Happening now!
#nevent1q…edke

2026-04-08 23:20:19 CEST

Streaming the 2nd and 3rd run of slow-to-validate blocks on Signet on YouTube now. Next run at 10pm UTC.
https://youtube.com/live/gHnrAlVA35A
context: https://delvingbitcoin.org/t/consensus-cleanup-demo-of-slow-blocks-on-signet/2367
Trying out @nprofile…qyec's "Zaps On Stream" for donations.

2025-11-19 15:37:39 CET

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yeah, seems to be VPN related
https://primal.net/e/nevent1qqs075tp595j209pnxfuwcac6lke5kk7qahv5cn85g3krpvq5hd8augua2uhw

2025-11-18 16:17:17 CET

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Ah, it seems GCP might be blocking my @nprofile…vfk0 connection?
I'm getting the following on all your pages:
<Error>
<Code>AccessDenied</Code>
<Message>Access denied.</Message>
</Error>

2025-11-18 15:54:19 CET

Hey @nprofile…yngf - I wanted to have a look at your Bitcoin Node census data, but the site seems to be down. Is this related to cloudflare?
https://census.yonson.dev

2025-07-29 17:45:26 CEST

I've written a bit about a project I've been working on for a while:
peer-observer: A tool and infrastructure for monitoring the Bitcoin P2P network for attacks and anomalies
https://b10c.me/projects/024-peer-observer/

2025-07-17 16:50:01 CEST

I have too many other projects currently, but I think this could be a fun side-project for someone:
Can we spot public spy-Electrum servers run by Chainanalysis?
https://github.com/0xB10C/project-ideas/issues/11

2025-06-25 16:40:59 CEST

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Where do I sign up?

2025-06-25 13:20:40 CEST

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🤙

2025-06-24 18:04:55 CEST

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should be fixed now

2025-06-24 17:06:03 CEST

I've persistent my notes on the May 2023 Bitcoin Core node DoS problems. These are background information for the disclosure from last year.
When non-ideal sorting, mass BRC-20 mints, and spy nodes caused a CPU Denial-of-Service on the Bitcoin network:
https://b10c.me/observations/15-inv-to-send-queue/?n

2025-05-11 00:19:16 CEST

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🤙

2025-05-09 10:03:42 CEST

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fwiw: here is a libbpf-rs tool using the mempool tracepoints: https://github.com/0xB10C/peer-observer/blob/3161b4c8e0acf8632522affbca459d41d351b097/extractor/src/main.rs#L302-L315

2025-04-16 15:27:50 CEST

In the current Bitcoin mining landscape with proxy lools like AntPool & friends, 6 mining pools produce and mine more than 95% of the block templates.
Bitcoin mining is highly centralized today.
https://b10c.me/blog/015-bitcoin-mining-centralization

2025-04-16 15:27:43 CEST

2025-01-16 15:46:22 CET

I had a closer look at 15 OFAC-sanctioned transactions recently reported as missing by my miningpool-observer. While all transactions were picked up in the following blocks, it seems like F2Pool started to filter them (again).
https://b10c.me/observations/13-missing-sanctioned-transactions-2024-12/

2024-10-11 12:19:19 CEST

Bitcoin Core: Disclosure of DoS due to inv-to-send sets growing too large
https://bitcoincore.org/en/2024/10/08/disclose-large-inv-to-send/
originally posted at https://stacker.news/items/718944

2024-08-02 14:08:19 CEST

Stats on compact block reconstructions
https://delvingbitcoin.org/t/stats-on-compact-block-reconstructions/1052
originally posted at https://stacker.news/items/632109

2024-07-15 17:04:23 CEST

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I usually say "zero ex B ten C" or just "B ten C"

2024-07-15 16:56:25 CEST

Mining Pool Game Theory during Forks
https://b10c.me/blog/014-mining-pool-game-theory-during-forks/
originally posted at https://stacker.news/items/609264

2024-07-11 15:53:27 CEST

mining pool game theory during forks
https://x.com/0xB10C/status/1811390920744468502
originally posted at https://stacker.news/items/604715

2024-06-18 17:12:06 CEST

Foundry won against AntPool's competing block by switching to their own block
https://x.com/0xB10C/status/1803082081385246738
Nothing crazy, just interesting to see this playing out.

2024-05-31 00:08:17 CEST

Who mined on which previous block during the fork at height 845626?
https://x.com/0xB10C/status/1780611768081121700

2024-04-19 23:18:43 CEST

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Thank you!

2024-04-19 22:45:04 CEST

25 blocks to go, halving stream is live
https://www.youtube.com/watch?v=C6D9OEjnWmA

2024-04-19 12:07:13 CEST

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Isn't that what my NIP-05 address is for?

2024-04-17 22:51:22 CEST

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Not too difficult, just time consuming

2024-04-17 17:59:11 CEST

Looking at the merkle branches that mining pools send to miners as part of stratum jobs, it's clear that the BTCcom pool, Binance pool, Poolin, EMCD, Rawpool, and possibly Braiins* have exactly the same template and custom transaction prioritization as AntPool.
https://image.nostr.build/33d5ac0f59082e8fbb5d02ccd9a50dccea43327ae97e10db06effaede7f7c064.jpg
Stratum v1 jobs include (parts of) the coinbase transaction and the merkle branches a miner needs to compute the merkle root. If all branches are equal across pools, the block template is exactly the same.
This is a smaller merkle-tree with the stratum job branches highlighted.
https://image.nostr.build/dab683037cc63f0e4805ae16561800dd342dd53dbb646c91e6c066044a51b2d6.jpg
Here, branch0 is the txid of the first transaction in the block after the coinbase.
In the AntPool/Binance/BTCcom/.. template, it's a manually prioritized transaction paying 9.03 sat/vbyte https://mempool.space/tx/c938e8027a7fba782a092695a53d37654021bf20df71ca91b4a6daa9198b0c73
Many of the other pools didn't prioritize a transaction and included the highest feerate transaction https://mempool.space/tx/96608dc747677d6dfbc3a2b37f8a0146abae132799b13c130066bd3716fdf91a paying 301 sat/vbyte. ViaBTC prioritized another transaction and has a vastly different template.
This indicates that F2Pool currently is not using the AntPool templates, even if they share the the same custody provider. We know from multiple occasions that F2Pool has been building their own templates (https://b10c.me/o11, https://b10c.me/o9, https://b10c.me/o8)
Note that SigmaPool and SecPool both seem to share the same template (distinct from AntPools template). Two names, but probably one pool.
Some overlap in the first branches of distinct pools is expected as these branches consist of few (usually high feerate) transactions. For example, Ocean's "default" and "core" templates overlap up to branch3. At least the first 15 tx (2⁴ - 1) in the template are equal.
* similar to EMCD in the picture, Braiins sometimes differs from AntPool in the later branches of the template. This could indicate they're only helping with AntPools transaction accelerator and directly syncing with AntPools mempool, causing occasional differences in templates.
I've heard speculation about this all being liked to an FPPS partnership with AntPool/Bitmain.
Bitmain insures against bad pool luck but you have to use Bitmains templates/transaction prioritization and pay the mining reward to the insurer for later distribution.
Essentially a pool of pools and a lot of mining centralization.

2024-04-02 13:17:10 CEST

Invalid F2Pool blocks 783426 and 784121 (April 2023)
https://b10c.me/observations/11-invalid-blocks-783426-and-784121/

2024-03-28 15:38:33 CET

Happy Birthday, LinkingLion!
A year ago I reported about LinkingLion, an entity that's presumably linking transactions to IP addresses and has been opening hundreds of connections per minute to my monitoring nodes.
An update: https://b10c.me/blog/013-one-year-update-on-linkinglion/

2024-03-28 15:37:46 CET

Update on LinkingLion: Reduced activity and a statement by LionLink Networks
https://b10c.me/blog/013-one-year-update-on-linkinglion/

2024-03-20 15:00:41 CET

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tl;dr: ViaBTC didn't check the header merkle root in their P2P client. Sending a block message with an old header and a modified coinbase transaction caused them to SPV mine on the old header for 30s at a time. I responsibly disclosed this to ViaBTC, and they awarded 2000 USDT.

2024-03-20 14:58:08 CET

In January, while investigating a misbehaving client on the Bitcoin P2P network, I found a vulnerability in ViaBTC's SPV mining code that allowed a remote attacker to waste their 60 EH/s hashrate by sending a single, crafted Bitcoin P2P message.
https://b10c.me/blog/012-viabtc-spv-vulnerability-disclosure/

2024-03-18 14:03:17 CET

ERROR: AcceptBlock: bad-witness-nonce-size…
You might have seen this in the debug log of your listening Bitcoin Core node. I dug into the origin and found that ViaBTC's mining server broadcasts mutated blocks without witness data:
https://b10c.me/observations/10-viabtc-blocks-without-witness-data/?n

2024-01-29 16:02:00 CET

I took a look at non-standard transactions in the last 117k blocks. Here's an overview:
https://b10c.me/observations/09-non-standard-transactions/?n

2023-11-22 09:01:25 CET

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They were all picked up by other miners

2023-11-21 13:08:16 CET

My miningpool-observer project recently reported six OFAC-sanctioned transactions as missing from blocks.
Four of these transactions were likely filtered by F2Pool. This is the first filtering based on OFAC sanctions I've seen.
More in: https://b10c.me/observations/08-missing-sanctioned-transactions?n

2023-09-28 17:26:46 CEST

wrote down my notes on the invalid block at height 809478
tl;dr: testing new mining pool software on mainnet can indeed get you burned - especially if it already didn't work on testnet
https://b10c.me/observations/07-invalid-block-809478

2023-09-27 11:24:12 CEST

MaraPool mined an invalid block at 809478 on mainnet. I observed the block on 9 out of 9 nodes.
ERROR: ConnectTip: ConnectBlock 000000000000000000006840568a01091022093a176d12a1e8e5e261e4f11853 failed, bad-txns-inputs-missingorspent, CheckTxInputs: inputs missing/spent
https://void.cat/d/3XxZTGnzrUdNhxHkCJ5ENg.webp

2023-05-29 17:32:07 CEST

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It's this one apparently: https://mempool.space/block/00000000000000000000ef263c1a23ba30872e9982352562df5e84115b806050

2023-05-11 00:13:17 CEST

more reorgs https://void.cat/d/J8YTKxTAnMTTY6evHzi3N.webp

2022-07-11 17:39:13 CEST

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add Iinux

2022-05-31 23:06:01 CEST

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do normal, animated PNGs work too? ![](https://b10c.me/data/mo/mo3-blockchaincom-recommendations/methodology.png)

2022-05-31 23:03:46 CEST