Developers in support of the Canderious Bitcoin Core Version 30 software update cheered today when Cryptographer invented a new way to spam the Bitcoin blockchain with images without using Op_return.
After months of civil war over the proper limitations of this scripting tool, this new method has shown that reducing the OP_Return DataCarrier allowance to zero does not interfere with any form of arbitrary data storage.
Op_return is the most popular storage area for large amounts of data that are unrelated to BTC intra-chain movement. Core is fighting the fork clients of node software, knots, for the maximum amount of data that two camps relay pending transactions or “Mempools” bitcoin network queues.
Core version 30 updates the default data carrier threshold to near 1MB, but prefers knots to near 80 bytes.
Unfortunately, as today’s findings demonstrate, neither setting can be guaranteed for any form of on-chain spam. Specifically, the Cryptographer stored JPEG images mainly inside a cleverly modified private key.
Spam Bitcoin blockchain with images in private key
In fact, Bitmex Research has created transactions that contain JPEGs that are stored primarily within private keys. Researchers intentionally used an insecure private key that could only come from on-chain data of the Bitcoin blockchain itself, which in a way the images were stored on the blockchain.
The clever method proves that users willing to save any data on the ledger can bypass OP_Return completely and store data using a valid, non-filterable consensus.
read more: Bitcoin core developers think it’s easy and interesting to attack knots
This method is unique and clever in the history of encryption, but some have listened to Claude Shannon’s work on spam prevention in the 1940s, pointing to the inevitability of those who avoid the op_return data filter.
The knot’s goal was not 100% spam prevention
While it is possible for dedicated users to store spam in Bitcoin ledgers using unconventional techniques, the Knots community has repeatedly emphasized that the OP_Return Mempool filter is effective, but incomplete deterrent for most spam.
“100% spam prevention is not our stated goal *- this is just a stupid strawman,” repeated the leader of the Knot community. He emphasized that broad deterrence through Mempool norms, rather than complete prevention, is the knot’s goal of limiting the Op_return output of Mempools.
“To this day, there are still people who claim that they think spam filters can stop 100% of spam,” he continued.
Bitmex Research has confirmed Bitcoin Core’s highly controversial decision to remove OP_Return data limits in version 30, scheduled for October. Bitmex Research highlighted the belief that the rate market is effective in reducing SPAM, rather than limiting Mempool’s policy.
