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consensus_defaults.go
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consensus_defaults.go
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package dagconfig
import (
"time"
"github.com/e4p1k0/pyipad/domain/consensus/utils/constants"
)
// The documentation refers to the following constants which aren't explicated in the code:
// d - an upper bound on the round trip time of a block
// delta - the expected fraction of time the width of the network exceeds defaultGHOSTDAGK
//
// For more information about defaultGHOSTDAGK, and its dependency on delta and defaultTargetTimePerBlock
// please refer to the PHANTOM paper: https://eprint.iacr.org/2018/104.pdf
//
// For more information about the DAA constants defaultDifficultyAdjustmentWindowSize, defaultTimestampDeviationTolerance,
// and their relation to defaultGHOSTDAGK and defaultTargetTimePerBlock see:
// https://research.kas.pa/t/handling-timestamp-manipulations/97
//
// For more information about defaultMergeSetSizeLimit, defaultFinalityDuration and their relation to pruning, see:
// https://research.kas.pa/t/a-proposal-for-finality-in-ghostdag/66/17
// https://research.kas.pa/t/some-of-the-intuition-behind-the-design-of-the-invalidation-rules-for-pruning/95
//
const (
defaultMaxCoinbasePayloadLength = 204
// defaultMaxBlockMass is a bound on the mass of a block, larger values increase the bound d
// on the round trip time of a block, which affects the other parameters as described below
defaultMaxBlockMass = 500_000
// defaultMassPerTxByte, defaultMassPerScriptPubKeyByte and defaultMassPerSigOp define the number of grams per
// transaction byte, script pub key byte and sig op respectively.
// These values are used when calculating a transactions mass.
defaultMassPerTxByte = 1
defaultMassPerScriptPubKeyByte = 10
defaultMassPerSigOp = 1000
// defaultMaxBlockParents is the number of blocks any block can point to.
// Should be about d/defaultTargetTimePerBlock where d is a bound on the round trip time of a block.
defaultMaxBlockParents = 10
// defaultGHOSTDAGK is a bound on the number of blue blocks in the anticone of a blue block. Approximates the maximal
// width of the network.
// Formula (1) in section 4.2 of the PHANTOM paper shows how to calculate defaultGHOSTDAGK. The delta term represents a bound
// on the expected fraction of the network life in which the width was higher than defaultGHOSTDAGK. The current value of K
// was calculated for d = 5 seconds and delta = 0.05.
defaultGHOSTDAGK = 18
// defaultMergeSetSizeLimit is a bound on the size of the past of a block and the size of the past
// of its selected parent. Any block which violates this bound is invalid.
// Should be at least an order of magnitude smaller than defaultFinalityDuration/defaultTargetTimePerBlock.
// (Higher values make pruning attacks easier by a constant, lower values make merging after a split or a spike
// in block take longer)
defaultMergeSetSizeLimit = defaultGHOSTDAGK * 10
defaultSubsidyGenesisReward = 1 * constants.LeorPerPyrin
defaultPreDeflationaryPhaseBaseSubsidy = 17 * constants.LeorPerPyrin
defaultDeflationaryPhaseBaseSubsidy = 14 * constants.LeorPerPyrin
defaultCoinbasePayloadScriptPublicKeyMaxLength = 150
// defaultDifficultyAdjustmentWindowSize is the number of blocks in a block's past used to calculate its difficulty
// target.
// The DAA should take the median of 2640 blocks, so in order to do that we need 2641 window size.
defaultDifficultyAdjustmentWindowSize = 2641
// defaultTimestampDeviationTolerance is the allowed deviance of an inconming block's timestamp, measured in block delays.
// A new block can't hold a timestamp lower than the median timestamp of the (defaultTimestampDeviationTolerance*2-1) blocks
// with highest accumulated blue work in its past, such blocks are considered invalid.
// A new block can't hold a timestamp higher than the local system time + defaultTimestampDeviationTolerance/defaultTargetTimePerBlock,
// such blocks are not marked as invalid but are rejected.
defaultTimestampDeviationTolerance = 132
// defaultFinalityDuration is an approximate lower bound of how old the finality block is. The finality block is chosen to
// be the newest block in the selected chain whose blue score difference from the selected tip is at least
// defaultFinalityDuration/defaultTargetTimePerBlock.
// The pruning block is selected similarly, with the following duration:
// pruning block duration =
// 2*defaultFinalityDuration/defaultTargetTimePerBlock + 4*defaultMergeSetSizeLimit*defaultGHOSTDAGK + 2*defaultGHOSTDAGK + 2
defaultFinalityDuration = 24 * time.Hour
// defaultTargetTimePerBlock represents how much time should pass on average between two consecutive block creations.
// Should be parametrized such that the average width of the DAG is about defaultMaxBlockParents and such that most of the
// time the width of the DAG is at most defaultGHOSTDAGK.
defaultTargetTimePerBlock = 1 * time.Second
defaultPruningProofM = 1000
// defaultDeflationaryPhaseDaaScore is the DAA score after which the pre-deflationary period
// switches to the deflationary period. This number is calculated as follows:
// We define a year as 365.25 days
// Half a year in seconds = 365.25 / 2 * 24 * 60 * 60 = 15778800
// The network was down for three days shortly after launch
// Three days in seconds = 3 * 24 * 60 * 60 = 259200
defaultDeflationaryPhaseDaaScore = 15778800 - 259200
defaultMergeDepth = 3600
)