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MoreBC2

src/pow.cpp

CategoryDeveloper / Source AtlasStatusReviewed / Source-confirmed partialLast reviewed2026-09-12

Purpose

Section titled “Purpose”

src/pow.cpp contains BitcoinII proof-of-work target validation and the current v31.1.0 ShockWave difficulty-adjustment implementation.

This page records externally important source behavior and links to the deeper ShockWave v31 review. Exact consensus behavior remains defined by the release-pinned implementation.

Current file-header licensing note

Section titled “Current file-header licensing note”

The notice in v31.1.0/src/pow.cpp places inherited Bitcoin Core and Dash/Darkcoin portions under their applicable MIT terms and gives original ShockWave implementation material separate terms that are not an open-source license.

MoreBC2 reports technical facts from review of that file. It does not reproduce or relicense the ShockWave implementation or source comments; the upstream notice controls rights in that material.

Activation

Section titled “Activation”

IsShockWaveEnabledForNextBlock() applies ShockWave when the candidate/next height is greater than or equal to params.nShockWaveActivationHeight.

Mainnet v31.1.0 sets:

nShockWaveActivationHeight = 57750

Therefore block height 57750 is the first mainnet block whose required work is determined by ShockWave.

Production next-work path

Section titled “Production next-work path”

GetNextWorkRequired() remains the production entry point used to obtain a candidate block’s required nBits.

Before activation it can use the inherited historical difficulty path. At and after activation it dispatches to ShockWave using recent chain state plus the candidate header.

That candidate-header input is operationally important because candidate time can affect the post-activation result.

ShockWave calculation scope

Section titled “ShockWave calculation scope”

Current release-pinned review establishes these externally useful properties:

  • a longer rolling sample of 25 block indexes / 24 completed timing intervals;
  • MedianTimePast-based timing endpoints for the longer sample;
  • a separate short-horizon view of the six most recent completed intervals;
  • normal next-target movement bounded relative to the preceding target, subject to powLimit;
  • recent-header timestamp consistency checks;
  • candidate-time emergency stall recovery;
  • future-time allowance accounted for before emergency easing begins;
  • recovery eligibility after 30 minutes of adjusted stall time, followed by additional source-defined easing steps at five-minute intervals;
  • post-event stabilization while the sampling window advances.

This page intentionally summarizes behavior rather than reproducing the implementation’s detailed internal rule catalogue.

Candidate-time / mining implication

Section titled “Candidate-time / mining implication”

Current src/node/miner.cpp recalculates required work when candidate time changes:

GetNextWorkRequired(previous_block, candidate_header, consensus_params)

A miner, pool, proxy, or template implementation that rolls nTime while retaining stale nBits can therefore construct an invalid BC2 candidate after ShockWave activation.

This is one of the main reasons generic Bitcoin/SHA-256d mining compatibility should not be assumed without BC2-specific qualification.

See Block-template assembly and Mining RPC.

Historical pre-ShockWave path

Section titled “Historical pre-ShockWave path”

BitcoinII retains inherited target-timespan and difficulty-interval parameters relevant to pre-activation history and inherited helpers:

  • target spacing: 10 minutes;
  • target timespan: 14 days;
  • historical adjustment interval: 2016 blocks.

Those values are not the current post-57750 mainnet difficulty schedule.

Proof-of-work target checks

Section titled “Proof-of-work target checks”

CheckProofOfWork() continues to validate the compact target and reject invalid or insufficient proof of work.

Reviewed behavior includes rejecting:

  • negative targets;
  • zero targets;
  • overflowed targets;
  • targets above powLimit;
  • hashes greater than the claimed target.

Chain selection boundary

Section titled “Chain selection boundary”

ShockWave changes how the required target for each new block is calculated. It does not replace BitcoinII’s accumulated-work chain-selection model.

Competing chain candidates are still evaluated through accumulated chain work in the validation/chain-selection path. Confirmation count is therefore not a separate protocol-finality rule; reorganization risk is fundamentally work-based.

See Life of a reorganization.

Dark Gravity Wave relationship

Section titled “Dark Gravity Wave relationship”

The src/pow.cpp notice attributes part of ShockWave’s rolling calculation to Dark Gravity Wave v3 concepts/code. That lineage does not make the complete BitcoinII algorithm identical to DGW.

Current documentation should use the name ShockWave for BitcoinII’s post-activation algorithm.

Header-sync interaction

Section titled “Header-sync interaction”

ShockWave requires more recent history than a single previous header target. BitcoinII v31.1.0 therefore carries bounded synthetic block-index history through its fork-aware header-sync path so header synchronization can call the production next-work logic.

See Fork-aware header synchronization.

Runtime boundary

Section titled “Runtime boundary”

MoreBC2 has current v31 node runtime evidence and isolated local block generation through generatetoaddress, but it has not yet executed controlled ShockWave vectors that vary candidate time and compare resulting nBits across normal, rapid-hashrate, and emergency-stall cases.

Activation thresholds and algorithm behavior on this page are source-confirmed rather than independently reproduced consensus test vectors.

Section titled “Related pages”

Primary sources

Section titled “Primary sources”

Pinned to BitcoinII Core v31.1.0:

  • src/pow.cpp
  • src/pow.h
  • src/kernel/chainparams.cpp
  • src/consensus/params.h
  • src/node/miner.cpp
  • src/headerssync.cpp

Canonical tag: https://github.com/Bitcoin-II/BitcoinII-Core/tree/v31.1.0

Verification

Section titled “Verification”

Status: Reviewed / Source-confirmed partial
Primary sources checked: BitcoinII Core v31.1.0 ShockWave, chain-parameter, miner, and header-sync paths
Notes: Activation, broad controller structure, target validation, candidate-time coupling, emergency timing, and historical/current difficulty boundary are source-backed. Independent controlled ShockWave runtime vectors remain open.