Grin, the developers will hold the first hardwork. What will change and how to prepare?

This summer was hot for hardforce. The nearest to this line is a cryptocurrency Zel, which after the upgrade will get a new algorithm of mining ZelHash and even more protection from ASIC. Then through the process of hard forks will Grin, and for developers it will be the first. Telling of what to expect from hard forks.

The contents

Hardforce Grin. Why do they need?

The current hardwork — not a random event. In August 2018 main developer Grin under the name of Igno Peverell published update details Proof of Work. Then the team agreed to hold updates every 262 080 units, that is, approximately every six months. As Grin started in mannete 17 January, mid-July is perfect for first fork.

See also: What is hardwork? Explain on the example of Bitcoin Cash.

The purpose of hard forks — do not give ASIC miners to capture the network and make their production meaningless. In this case we recall that the second algorithm CuckAToo-31 is designed for ASIC, while it supports the graphics card 11 GB.

Update Grin

Testnet new version of the network launched on June 23 unit number 185 040. He debut hardwork Grin will be held at block 262 080. Roughly expect it is July 17, 2019 at 09:28:28 Moscow time. The countdown to the events live is happening on this page.

Source: Coingecko

After carrying out the update will work only version nod, wallets and miners Grin from 2.0.0 and above.

Before proceeding to the list of innovations, we note an important point. When you upgrade the network to Grin v2.0.0 users just need to update their nodes. Anything extra is not necessary to do so beware of a possible Scam with offers to download a third party program or something like that. This can result in the loss of funds.

That will change hardwork Grin

Innovation will be a lot, so consider them from two points of view. The first are the nodes.

Changes to gcd Grin:

  • the updated algorithm Proof-of-Work — Grin developers continue to struggle with manufacturers of ASIC miners, so change Cuckaroo29 on Cuckarood29. Details about the latter as described below;
  • changes to the API node , you need to change the endpoint v1/pool/push on v1/pool/push_tx. This will provide a small incompatibility for wallets that will prevent the communication of wallets to version 2.0.0 with the same node.

Changes to the wallet:

  • changes to the scheme “bulletproof rewind” (rewind bulletproof) — the new scheme will make the wallet more flexible and adds the ability to hide information;
  • change to V2 API — the API REST V1 replaced by V2 JSON-RPC API. Documentation is available at the link here and here;
  • changes for V0 Slate — originally it was created for the Grin version 1.0.2. Now it will be compatible with this new version.

What feature of the new algorithm Cuckarood29?

Additional PoW algorithm-hashing Grin called Cuckaroo29 performed perfectly. Since the launch of mannata network it does not show traces of ASIC is confirmed by the developer under the name tromp. The members of the team know about the scheduled release of ASIC miners this summer, so the transition to Cuckarood29 to be.

Let’s start with the theory. Conventional Cuckaroo there are three separate aspects that can be changed by the developers:

  1. the main hash function — at the moment it is siphash-2-4;
  2. calculating end points of a block of ribs;
  3. the type of cycle.

Members of the team left second paragraphs and do the rest. In the end, changed siphash defined using the templates on one of the values of rotation.

template < int rotE = 21 >
class siphash_state {
void sip_round() {
v0 += v1; v2 += v3; v1 = rotl(v1,13);
v3 = rotl(v3,16); v1 ^= v0; v3 ^= v2;
v0 = rotl(v0,32); v2 += v1; v0 += v3;
v1 = rotl(v1,17); v3 = rotl(v3,rotE);
v1 ^= v2; v3 ^= v0; v2 = rotl(v2,32);

A new type of cycle is a directed (directed). Half edges (with even index) is directed from U to V, while the second half (with odd index) is directed from V to U. we Can also say that the cycle must alternate between odd and even indexed edges. At the same time, the number of nodes in each U and V twice. So Cuckarood29 will have 2^28 U-nodes, and 2^28 U->V edges and 2^28 V->U edges. As a result, this leads to doubling of the expected number of cycles.

See also: How mine Grin? Settings, the profitability of production and the right equipment.

The developers will not make changes in the complexity of mining. So if half of the current Cuckaroo29 miners will not be able to be updated, the speed of decisions in the secondary PoW will remain the same. If all will be updated in time, the average blocktime may fall to 36 seconds. In this case the coefficient ar_scale will be reduced for compensation, and the situation will return to normal for several hours.

About the name. Added the letter “d” in Cuckarood29 basically means “directed”, that is “directed”, although by analogy with SHA256d can also mean “doubling”, that is “doubling” (solutions).

How to prepare for the hard forks?

By tradition, we will specify the necessary actions for all market participants.


Have miners Grin on the algorithm C31 all good — nothing not need to be updated. The miners C29 have to be updated to the latest version of grin-miner or to download a software update that is compatible with Cuckarood29.

Source: Bitcoinist

Miners 2Miners to worry about. The pool will automatically switch to the new algorithm and continue to work.


The owners of the exchanges need to do the following:

  • to update Grin to v2.0.0 or higher;
  • update Grin-wallet to v2.0.0 or above, and the transaction will only be created after hard forks;
  • to upgrade the infrastructure of the exchange under the wallet API V2.


  • to update Grin to v2.0.0 or higher;
  • update Grin-wallet to v2.0.0 or above. The transaction also will be created only after hard forks;
  • upgrade infrastructure under the pool wallet API V2;
  • mining-pool 2Miners ready for the hard forks.


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