// Compute quality of the answer. Also builds a verifier
// return: quality in float64
func (c *Client) Quality(challenge []byte, a block.Answer) float64 {
nodes := c.verifier.SelectChallenges(challenge)
if !c.verifier.VerifySpace(nodes, a.Hashes, a.Parents, a.Proofs, a.PProofs) {
return -1
}
all := util.Concat(a.Hashes)
answerHash := sha3.Sum256(all)
x := new(big.Float).SetInt(new(big.Int).SetBytes(answerHash[:]))
num, _ := util.Root(x, a.Size).Float64()
den := math.Exp2(float64(1<<8) / float64(a.Size))
return num / den
}
func NewBlock(old *Block, prf PoS, ts []Transaction, signer crypto.Signer) *Block {
oldH, err := old.Hash.MarshalBinary()
if err != nil {
panic(err)
}
prevHash := sha3.Sum256(oldH)
h := Hash{
Hash: prevHash[:],
Proof: prf,
}
var tsBytes []byte
for i := range ts {
b, err := ts[i].MarshalBinary()
if err != nil {
panic(err)
}
tsBytes = append(tsBytes, b...)
}
sigBytes := util.Concat([][]byte{old.Sig.Tsig, old.Sig.Ssig})
tsig, err := signer.Sign(rand.Reader, tsBytes, crypto.SHA3_256)
if err != nil {
panic(err)
}
ssig, err := signer.Sign(rand.Reader, sigBytes, crypto.SHA3_256)
if err != nil {
panic(err)
}
sig := Signature{
Tsig: tsig,
Ssig: ssig,
}
b := Block{
Id: old.Id + 1,
Hash: h,
Trans: ts,
Sig: sig,
}
return &b
}