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fix PowerCmp

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This commit is contained in:
Łukasz Magiera 2019-10-28 21:28:01 +01:00
parent 563c0e494e
commit e98feb4a39
1 changed files with 3 additions and 3 deletions
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6
chain/types/blockheader.go
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@ -166,21 +166,21 @@ func PowerCmp(eproof ElectionProof, mpow, totpow BigInt) bool {
/*
Need to check that
h(vrfout) / max(h) * e < minerPower / totalPower
h(vrfout) / max(h) < e * minerPower / totalPower
max(h) == 2^256-1
which in terms of integer math means:
h(vrfout) * totalPower * e < minerPower * (2^256-1)
h(vrfout) * totalPower < e * minerPower * (2^256-1)
*/
h := sha256.Sum256(eproof)
lhs := BigFromBytes(h[:]).Int
lhs = lhs.Mul(lhs, blocksPerEpoch.Int)
lhs = lhs.Mul(lhs, totpow.Int)
// rhs = minerPower * 2^256 - minerPower
// rhs = minerPower << 256 - minerPower
rhs := new(big.Int).Lsh(mpow.Int, 256)
rhs = rhs.Mul(rhs, blocksPerEpoch.Int)
rhs = rhs.Sub(rhs, mpow.Int)
return lhs.Cmp(rhs) == -1