What if top fidelity bonds in the orderbook are actually controlled by the same person? They would be foregoing about 8.39 BTC² in sacrificed value, nearly twice as much as the total value right now which is 4.51 BTC². And their success rate would only be about 6% per coinjoin

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In terms of sybil resistance, if a taker does a coinjoin with 10 other makers (the default value), then in order to successfully attack a sybil attacker would have to lock up over 128k BTC (6.1 billion USD) for one year, or destroy 160 BTC forever

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Fidelity bonds are a mechanism for resistance against such sybil attacks. Honest makers in JoinMarket are now incentivized to lock up bitcoins using the OP_CHECKLOCKTIMEVERIFY opcode. For a sybil attacker to be successful they have to lock up a huge amount of bitcoins

Currently 264 BTC are locked up, including this one maker who locked up 124 coins for one year. Several other makers have locked up tens of bitcoins each some for multiple years.

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Thread on developments exactly one month since Fidelity Bonds were added to JoinMarket

JoinMarket used to work by the user's wallet randomly choosing market makers out there to do a coinjoin with, but what if all those makers were actually controlled by the same person? That attacker could unmix all the coinjoins and spy on users, this is called a sybil attack

Right now in JoinMarket: if a fidelity-bond-aware taker does a coinjoin with 6 makers, a sybil attacker would have to lock up 19303 BTC for 1 year or burn 24 BTC to successfully attack

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New release of Joinmarket.

Includes use of fidelity bonds (think: timelocked outputs acting as "skin in the game" to prevent Sybil attacks):


Release notes give the necessary details as usual.

Haven't seen this being shared anywhere, but this is a great site for looking up various metrics (liquidity, volume, median fees etc) of Whirlpool, Wasabi and Joinmarket, as well as other on-chain stats:


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Bitcoin Optech newsletter #153 is here:

- celebrates the lock-in of the taproot soft fork
- describes a draft BIP for improving transaction privacy by varying the fields used to implement anti fee sniping
- features an article about the challenges of combining transaction replacement with payment batching
- announces Rust Bitcoin 0.26.2, Rust-Lightning 0.0.98, LND 0.13.0-beta.rc5


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Really worth a read on current developments in Bitcoin in China:


"Once both sides agree on a price, the buyer will use a separate payments platform -- operated by their bank or a fintech company like Ant Group Co. -- to send yuan to the seller. The digital coins, usually held in escrow by the OTC platform until the yuan payment clears, are then transferred to the buyer. Chinese regulators often have no way to connect one step of the transaction to the other."

New release of Electrum Personal Server. Fixed issue with lag for large mempools, most users would just disable the mempool histogram for large mempools, with this update that is no longer an issue. Also, now slightly easier to run with automating tools like systemd. Connect your Electrum wallet to your own full node today!

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Joinmarket does 650 BTC or ~ 38M USD volume in one day...

... is the clickbait statistic I would use if I didn't know it's pretty stupid to measure like that 😂

(how? first:
h/t @openoms for using the `snicker-finder.py -j` script I recently mentioned on recent blocks - from 682603 to 682795, roughly 1.3 days' worth). From earlier experiments, this is higher than average, but not stupidly so. Also h/t @kristapsk for his transaction parser script for easier reading the output. Data: ...(1/n)

I will run...

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Releasing a client with a name "Bitcoin Core 0.21.0-based Taproot Client 0.1" is a scammer trick. It's not Bitcoin Core.

I suppose if you can't convince people with reason, trick them with dishonesty.

I just added a section to the bitcoin wiki explaining how address reuse can also harm censorship resistance as well a privacy: en.bitcoin.it/wiki/Address_reu

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