kcalvinalvin

Verifying a bitcoin block as an utreexo compact state node

A utreexo compact state node doesn't have all the data required for verifying a bitcoin block just with the block. It also requires a utreexo proof.

The method described here is only valid for utreexod v0.4.1. The next version will have a different P2P messaging flow.

For v0.4.1, to get the necessary utreexo data, one must ask for a MSG_UTREEXO_BLOCK when constructing the getdata. Since we also want segwit blocks as well, we use the

kcalvinalvin

Add

Utreexo accumulator is a collection of proper merkle trees. All the merkle trees have 2 children or none.

Below is an example of adding 7 leaves to the tree. You can run the code I used to generate this at https://go.dev/play/p/um5263SDk59

This is an accumulator with 1 leaf. It has 1 root, which is also a leaf.

kcalvinalvin

package patriciaaccumulator

import (
        "encoding/hex"
        "fmt"
        "os"
        "path/filepath"
        "testing"
)

kcalvinalvin

diff --git a/bridgenode/genproofs.go b/bridgenode/genproofs.go
index 36f1117..cca31b8 100644
--- a/bridgenode/genproofs.go
+++ b/bridgenode/genproofs.go
@@ -110,6 +110,7 @@ func BuildProofs(
        logrus.SetOutput(logfile)
        logrus.SetLevel(logrus.InfoLevel)
        for ; height != knownTipHeight && !stop; height++ {
+               fmt.Println("on block", height)