I have decided that I would no longer like to be a member of Bitcoin Unlimited. The reason is that I feel Bitcoin Unlimited, as an organization, is too closely associated with the Bitcoin SV community.

The event that really decided my opinion is the lawsuit against several people in the Bitcoin Cash community, including the developers Amaury Séchet, Jason Cox, and Shammah Chancellor. These are my friends and colleagues, and using a frivolous lawsuit to target them with the force of law in this manner is despicable worthy of condemnation. While the parties responsible for this aggression seem to…

Note (2021–02–01): After the original publication of this article, the Bitcoin Cash network separated into two versions during the November 15, 2020 upgrade. Bitcoin ABC is now developing Avalanche technology for deployment on the BCHA network, not for Bitcoin Cash.

Abstract: The Avalanche protocol is a robust consensus algorithm, with proofs of its Byzantine Fault Tolerant (BFT) properties. It has different properties than Proof of Work (PoW), which makes it suitable to be used as a complement to PoW. Using both algorithms where they are strongest would allow Bitcoin Cash to enjoy the benefits of both Avalanche and PoW.


Abstract: This article describes the design of an opcode recently added to the Bitcoin Cash scripting language called “OP_CHECKDATASIG” [1]. This opcode was activated on the Bitcoin Cash network during the recent upgrade. It allows Script to validate arbitrary messages from outside the blockchain, opening up many exciting possible use cases (see Appendix A).

An earlier version of this article was originally published at Yours.org [11].


When someone sends a Bitcoin Cash transaction, they sign it to prove to the network that the owner of the private key authorizes the transaction. The signature is typically verified using an opcode called…

There have recently been several articles, interviews and videos related to Bitcoin’s BTC/BCH divide that appeal to superficial aspects of Austrian School economics, arguing that BTC upholds Austrian ideas, and portraying BCH as more Keynesian. These arguments, however, miss the underlying reasons needed to support their position. They merely appeal to surface appearances, and in that way are similar to a cargo cult.

Cargo cults were an interesting phenomenon in various Pacific island societies where they would emulate superficial aspects of advanced societies, with the goal of attaining the benefits they had observed [1]. For example, they would construct crude…

For many years, there has been a recurring argument against on-chain scaling based on the idea that the blockchain is a “database that must store everything, forever”. This argument is often accepted uncritically, even among some big-blockers who accept the premise, but argue that larger blocks are still feasible even with all nodes “storing everything forever”.

The recent emergence of applications such as Memo (memo.cash) has raised concerns for some Bitcoin Cash proponents [1]. …

Note: This article was originally published at Yours.org

In the last few weeks, several new candidates for Bitcoin Cash’s new difficulty adjustment algorithm have emerged. Some of these proposed algorithms have been incorporated into Kyuupichan’s model [1], which attempts to simulate miners moving hash power based on their economic incentives.

Deadalnix has proposed a simpler version of his algorithm [2]. It still uses chain work to calculate a difficulty based on estimated hash rate, but his new proposal replaces the two targeting windows with one 144-block window. It is labelled as “cw-144” in Kyuupichan’s model.

One of the problems with…

Note: This article was previously published at Yours.org

This article describes the difficulty targeting algorithm proposed for Bitcoin Cash by Kyuupichan (Neil Booth), announced and then updated on the bitcoin-ml mailing list [1, 2], and implemented at https://reviews.bitcoinabc.org/D578 [3].

A previous article described another proposal by Deadalnix [4].


The goals of Kyuupichan’s design are:

  1. Have an algorithm that is simple to understand, and easy to implement for SPV clients.
  2. Retain a long-term mean block interval of about 600 seconds.
  3. Adjust difficulty each block if necessary, but only by small fraction, using a 6-block window to avoid oscillations. …

Note: This article was originally published at Yours.org

The purpose of this article is to describe the difficulty targeting algorithm that has been proposed for Bitcoin Cash by Amaury Sechet (Deadalnix). The algorithm was originally announced on the bitcoin-ml mailing list on Aug 25 2017 [1], and was subsequently implemented at https://reviews.bitcoinabc.org/D571 [2]. I previously published an article outlining the difficulty targeting issue [3], the current article goes into more detail explaining the specifics of this particular proposal.

Another proposal by kyuupichan can be found at: https://reviews.bitcoinabc.org/D578 [4].


The goals of the design are:

  1. Adjust difficulty to hash rate to…






为了处理这些问题,竞争币想出了各种具有创新性的难度算法,例如Kimoto Gravity Well[1]、MIDAS[2]、Dark Gravity Wave(达士币)[3]和digishield(DigiByte、) [4, 5, 6]。这些难度算法在不同的目标之间做出各种权衡取舍。例如,应对算力的突变、防止时间戳被操纵,区块生产(以及通胀)计划的准确目标定位。我知道的这些折衷方案中,分析得最全面的是致力于Cryptonote难度调整算法的zawy12 。

Note: This article has been kindly translated into Chinese

It has been almost a month since Bitcoin successfully split into two descendants: Bitcoin and Bitcoin Cash. The hard fork that marked the birth of Bitcoin Cash created some new rules for this offspring currency, most notably the removal of the 1MB block size limit that was hobbling Bitcoin’s growth. But there were also other important changes that were implemented to allow Bitcoin Cash to split cleanly and coexist with Bitcoin.

One of these additional changes is known as the Emergency Difficulty Adjustment (EDA). The EDA was implemented as a relatively…

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