46 lines
1.3 KiB
Go
46 lines
1.3 KiB
Go
package pow
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import (
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"encoding/hex"
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"math"
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"strconv"
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sdk "github.com/cosmos/cosmos-sdk/types"
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"github.com/tendermint/tendermint/crypto"
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)
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// generate the mine message
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func GenerateMsgMine(sender sdk.AccAddress, count uint64, difficulty uint64) MsgMine {
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nonce, hash := mine(sender, count, difficulty)
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return NewMsgMine(sender, difficulty, count, nonce, hash)
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}
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func hash(sender sdk.AccAddress, count uint64, nonce uint64) []byte {
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var bytes []byte
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bytes = append(bytes, []byte(sender)...)
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countBytes := strconv.FormatUint(count, 16)
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bytes = append(bytes, countBytes...)
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nonceBytes := strconv.FormatUint(nonce, 16)
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bytes = append(bytes, nonceBytes...)
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hash := crypto.Sha256(bytes)
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// uint64, so we just use the first 8 bytes of the hash
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// this limits the range of possible difficulty values (as compared to uint256), but fine for proof-of-concept
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ret := make([]byte, hex.EncodedLen(len(hash)))
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hex.Encode(ret, hash)
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return ret[:16]
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}
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func mine(sender sdk.AccAddress, count uint64, difficulty uint64) (uint64, []byte) {
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target := math.MaxUint64 / difficulty
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for nonce := uint64(0); ; nonce++ {
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hash := hash(sender, count, nonce)
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hashuint, err := strconv.ParseUint(string(hash), 16, 64)
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if err != nil {
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panic(err)
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}
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if hashuint < target {
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return nonce, hash
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}
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}
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}
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