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.

A…

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].

Background

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].

Goals

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].

Goals

The goals of the design are:

  1. Adjust difficulty to hash rate to…

从比特币成功分裂成两条链(比特币和比特现金)已经快一个月了。硬分叉诞生了比特现金,也为这个新生的货币创建了一些规则,最引人注目的就是移除了阻碍比特币发展的1MB区块大小限制。但是,还部署了其他一些很重要的改变,以便让比特现金可以彻底分裂并与比特币共存。

其中一项额外的更改叫做紧急难度调整(EDA)。部署EDA是一种相对安全且最小的更改,可以在比特现金的算力还很小的时候,通过下调难度值使比特现金可以存活下去。现在,EDA已经部署(到网络),这个决定是合理的。因为分裂后的情况是无法预知的,所以部署一个改变最小的方案让比特现金可以在算力很小的时候存活下去是明智的,但是,如果比特现金迅速得到了大量的算力支持,难度也有可能保持不变。

现在已经进行分裂,我们得到了关于比特现金实际情况的信息。我们现在知道,比特现金目前的算力很小,而我们获得的经验是EDA机制虽然使比特现金得以存活,但是并不是最佳解决方案,因为它导致比特币和比特现金之间的算力摇摆不定。

难度值难题

算力不稳定的问题在竞争币社区已争论多年。多个矿池(在矿池中矿工可以快速用工作证明算法进行挖矿)导致算力摇摆不定,缺乏稳定性。这种算力的快速转换经常会导致交易确认时间无法预测,以及长期出块速度慢,还有更严重的问题,各种币的市值差距太大会导致市值较小的币容易受到玩弄难度算法和操纵时间戳的矿工的攻击。

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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