Thinking about different difficulty adjustments for protecting new coins against attacks from big miners. 2017 when BCH forked from BTC, BCH added the EDA (emergency difficulty adjustment) and updated later to DAA ( difficulty adjustment algorythm ). Another approach of protecting the blockchain is DigiShield, the difficulty adjustment that is used by Dogecoin. What is the difference between DigiShiel and the DAA of BCH ? Wich difficulty adjustment is better and why ?

2 Answers 2


Just because someone has made something and given it a name doesn't mean that it isn't utter garbage. Don't trust any review or analysis from anyone that can't give you clear and well reasoned list of criteria that it is necessary and sufficient for a difficulty update algorithm to achieve.

Some of the fad options that altcoins blindly copy don't even achieve the basic property of achieving the target block interval when hashrate is constant.

Instead they seem to obsess about falling back to the nominal rate when hashrate suddenly spikes, ignoring that slow blocks are a safe failure mode and completely failing to consider the security side effects of their decision. We've seen at least a few hyped difficulty update changes lead to actual attacks, not just theoretical weaknesses.

I have no doubt that its possible to make something that is pareto-superior to bitcoin's non-overlapping rectangular window, but I am equally sure that essentially all the other things you see hyped fail to do so. This is unsurprising because instead of starting with a meta-analysis to understand what properties are useful, they all seem to have been created by changing things and analyzing only one or two properties (or not even analyzing things at all).

Keep in mind the primary purpose of most technical changes in most altcoins is to create marketing bulletpoints that can be used to convince unsophisticated speculators to pay for the altcoin. This marketing requires a lot of hype-- far in-excess of whatever hyper a theoretical 'perfect' difficulty update would deserve-- but not a lot of substance.


They used this simulator decide on a DAA for Bitcoin Cash. Although DigiShield is not a part of the DAA collection of it, a review of it can be found here and here.

  • Thank you very much for your answer. But what you think is better DAA or Digishield ?
    – laizess
    Commented Dec 15, 2018 at 14:51

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