BIP-110: The Hidden Threat of Bitcoin Loss During Network Splits
On the eve of a possible soft fork related to the activation of BIP-110, a serious security threat is brewing on the market for holders of the first cryptocurrency. My analysis shows that an attempt to take advantage of "free" coins from the chain split could result in a direct loss of real bitcoins.
The mechanics of the double balance
The essence of the problem lies in the very mechanism of the blockchain split. At the moment of the fork, owners form a double balance: the same volume of assets is reflected in both versions of the network. However, this is exactly where the trap is hidden. In the early stages, transactions are valid in both chains. By signing a transfer of fork tokens, the user inadvertently creates a ready-made template for an identical operation in the main network.
Attackers can intercept this template and reproduce the transaction in the main chain, debiting an equivalent amount in real bitcoins from the same address. In this case, fees are deducted twice, and the wallet is not zeroed out — exactly the volume that was declared for sale is lost. The most vulnerable will be large holders, whose operations will attract maximum attention.
The only reliable strategy in this situation is to keep assets completely immobile. To copy a transaction, a signed operation is required, and if there is none, there is nothing to reproduce.
Historical context and causes of the conflict
Bitcoin has already faced a similar challenge. After the Bitcoin Cash split in 2017, developers had to implement a special protective mechanism in the new network to prevent the transfer of transactions between chains. The BIP-110 specification lacks such protection, making the situation especially dangerous.
The dispute has been ongoing since the fall of 2025, when the release of Bitcoin Core v30 raised the OP_RETURN field limit from 80 to 100,000 bytes. Critics considered that this would simplify clogging the blockchain with extraneous information, and in December the Bitcoin Knots team proposed BIP-110, limiting the volume of non-payment data for a year. To activate, the initiative needs confirmation from 1109 of 2016 blocks, but currently only about 2.6% of blocks contain the flag.
However, the authors provided a backup scenario. Starting from block #961,632, expected on August 8, nodes with BIP-110 will begin rejecting blocks without the required flag. Since almost the entire hash rate does not set it, these nodes will stop following the main chain. But for an actual split, miners willing to mine blocks under the new rules are needed. If none are found, the alternative chain simply will not appear.
Restrictions on non-payment data will take effect later — from block #965,664 in early September. Until that moment, both networks will be able to accept the same operations. To safely separate assets, the owner will first have to obtain coins that exist only in one branch, and only then use them to separate one balance from another. Mining speed could shift both dates by about a day.
My verdict: The situation around BIP-110 is a classic example of how technical disagreements create real risks for end users. In the absence of built-in protection against transaction replay, anyone who tries to "sell" fork tokens is playing with fire. I recommend that all bitcoin holders exercise maximum caution and refrain from any operations during the period of uncertainty.