Bitcoin (BTC) miners openly using AsicBoost are at present comprising 63% of its network hashrate. This vindicates community concerns from 2022 that accused Bitmain of using the "covert" version of AsicBoost.

The statistic was highlighted on March 9 past Bitmex Enquiry, building on a similar report from Dec 2022. Though the overt AsicBoost was only used by 30% of miners at the time, the analysts argued that the 2022 controversy was largely settled. They wrote:

"If covert AsicBoost was used by some miners to obtain a secret reward, with significant adverse effects on Bitcoin, this problem now appears mostly solved."

Bitmain was the target of strong criticism from notable Bitcoiners in 2022 afterward it allegedly introduced covert AsicBoost into its hardware. The visitor was also chastised for opposing the network'due south Segregated Witness (SegWit) upgrade — a proposal which would take limited the usefulness of their covert AsicBoost tactics.

What is AsicBoost?

AsicBoost is the proper noun of a technique adult by cryptography experts, Timo Hanke and Sergio Lerner. The solution was patented under a framework named "Blockchain Defensive Patent License," which was specifically designed to limit competitive advantages in mining and preserve network security.

In a Proof of Work organization, miners must generate a cryptographic hash of some important block data, which is contained in the block header. In guild to make it a difficult task, the hash must satisfy the "difficulty" condition, which generally requires it to be lower than a certain number. Since hash functions are completely unpredictable, the merely way to satisfy the status is to but try many different combinations of input data.

AsicBoost exploits the fact that Bitcoin block hashes are created from separate chunks of 64 bytes of data. Since the entire header is fourscore bytes, there are two chunks that need to be hashed during the mining procedure.

Structure of a block header

Structure of a block header. Source: Bitmex Research

With the technique, one of the chunks tin can remain unmodified over multiple hashing attempts, which saves resources. The deviation between overt and covert AsicBoost lies in which chunk is kept unchanged.

Nether overt AsicBoost, the "version" bytes are used as an extra nonce to modify the resulting hash. Thus, the 2d clamper does not change for a number of attempts.

With covert AsicBoost, miners need to shuffle or fifty-fifty remove transactions in order to go on the last four bytes of the Merkle root — the signature of the block'due south transactions — unchanged.

While the latter technique is less efficient, it is more difficult to detect and thus would permit a miner to maintain a competitive advantage. Crucially, the activation of SegWit would have broken the exploit.

Bitmain criticized for using covert AsicBoost

In April 2022, news broke that Bitmain had implemented the covert AsicBoost exploit in its hardware. The discovery was made by Gregory Maxwell, at the time CTO of Blockstream.

The findings were used by the community to allege that Jihan Wu — Bitmain CEO and strong SegWit critic — had ulterior motives for his position.

AsicBoost was estimated to increase mining performance past 20-xxx%. Andreas Antonopolous and others argued that covert AsicBoost would somewhen destabilize the network, equally some miners would have an unfair advantage.

Bitmain cleaning up

The ever-increasing effigy of overt AsicBoost miners, currently at about 63%, means that the advantage of using it covertly is dwindling.

Even if at that place are fewer incentives of foul play now, in a conversation with Cointelegraph, Kristy Leigh-Minehan noted that Bitmain "cleaned upwards its act" in preparation for the initial public offering (IPO).

The initial plans of the 2022 IPO were thwarted by a protracted bear market place. Though a new endeavor in late 2022 was discovered, internal company bug prevented it from continuing.

The force per unit area from the Bitcoin halving has allegedly forced Bitmain to slash over 50% of its staff. Even though some may have hoped for a halving-induced rally, the already-significant cut may not be enough to sustain the company amid a global marketplace panic just two months before the upcoming block reward decrease.