Elichai Turkel 45edacfbfa
Replace Double-SHA256 with blake2b and implement domain seperation (#1245)
* Replace default hasher (Double-SHA256) with domain seperated blake2b

* Replace all hashes with domain seperated blake2b

* Update the genesis blocks

* Replace OP_HASH256 with OP_BLAKE2B

* Fix the merkle tree by appending zeros instead of duplicating the hash when there is 1 branch left

* Update tests

* Add a payloadHash function

* Update gitignore to ignore binaries

* Fix a bug in the blake2b opcode
2020-12-21 12:51:45 +02:00

52 lines
2.0 KiB
Go

package pow
import (
"github.com/kaspanet/kaspad/domain/consensus/model/externalapi"
"github.com/kaspanet/kaspad/domain/consensus/utils/consensushashing"
"github.com/kaspanet/kaspad/domain/consensus/utils/hashes"
"github.com/kaspanet/kaspad/domain/consensus/utils/serialization"
"github.com/kaspanet/kaspad/util"
"github.com/pkg/errors"
"math/big"
)
// CheckProofOfWorkWithTarget check's if the block has a valid PoW according to the provided target
// it does not check if the difficulty itself is valid or less than the maximum for the appropriate network
func CheckProofOfWorkWithTarget(header *externalapi.DomainBlockHeader, target *big.Int) bool {
// The block pow must be less than the claimed target
powNum := calcPowValue(header)
// The block hash must be less or equal than the claimed target.
return powNum.Cmp(target) <= 0
}
// CheckProofOfWorkByBits check's if the block has a valid PoW according to its Bits field
// it does not check if the difficulty itself is valid or less than the maximum for the appropriate network
func CheckProofOfWorkByBits(header *externalapi.DomainBlockHeader) bool {
return CheckProofOfWorkWithTarget(header, util.CompactToBig(header.Bits))
}
func calcPowValue(header *externalapi.DomainBlockHeader) *big.Int {
// Zero out the time and nonce.
timestamp, nonce := header.TimeInMilliseconds, header.Nonce
header.TimeInMilliseconds, header.Nonce = 0, 0
prePowHash := consensushashing.HeaderHash(header)
header.TimeInMilliseconds, header.Nonce = timestamp, nonce
// PRE_POW_HASH || TIME || 32 zero byte padding || NONCE
writer := hashes.NewPoWHashWriter()
writer.InfallibleWrite(prePowHash[:])
err := serialization.WriteElement(writer, timestamp)
if err != nil {
panic(errors.Wrap(err, "this should never happen. Hash digest should never return an error"))
}
zeroes := [32]byte{}
writer.InfallibleWrite(zeroes[:])
err = serialization.WriteElement(writer, nonce)
if err != nil {
panic(errors.Wrap(err, "this should never happen. Hash digest should never return an error"))
}
return hashes.ToBig(writer.Finalize())
}