lotus/storage/sealer/commitment/commr.go

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package commitment
import (
"math/big"
"os"
"path/filepath"
"github.com/triplewz/poseidon"
ff "github.com/triplewz/poseidon/bls12_381"
"golang.org/x/xerrors"
)
const pauxFile = "p_aux"
func CommR(commC, commRLast [32]byte) ([32]byte, error) {
// reverse commC and commRLast so that endianness is correct
for i, j := 0, len(commC)-1; i < j; i, j = i+1, j-1 {
commC[i], commC[j] = commC[j], commC[i]
commRLast[i], commRLast[j] = commRLast[j], commRLast[i]
}
input_a := new(big.Int)
input_a.SetBytes(commC[:])
input_b := new(big.Int)
input_b.SetBytes(commRLast[:])
input := []*big.Int{input_a, input_b}
cons, err := poseidon.GenPoseidonConstants(3)
if err != nil {
return [32]byte{}, err
}
h1, err := poseidon.Hash(input, cons, poseidon.OptimizedStatic)
if err != nil {
return [32]byte{}, err
}
h1element := new(ff.Element).SetBigInt(h1).Bytes()
// reverse the bytes so that endianness is correct
for i, j := 0, len(h1element)-1; i < j; i, j = i+1, j-1 {
h1element[i], h1element[j] = h1element[j], h1element[i]
}
return h1element, nil
}
// PAuxCommR reads p_aux and computes CommR
func PAuxCommR(cache string) ([32]byte, error) {
commCcommRLast, err := os.ReadFile(filepath.Join(cache, pauxFile))
if err != nil {
return [32]byte{}, err
}
if len(commCcommRLast) != 64 {
return [32]byte{}, xerrors.Errorf("invalid commCcommRLast length %d", len(commCcommRLast))
}
var commC, commRLast [32]byte
copy(commC[:], commCcommRLast[:32])
copy(commRLast[:], commCcommRLast[32:])
return CommR(commC, commRLast)
}