blockchain sandbox: UTXO chain, p2p mining, attacker node

cmd/attack/main.go

@@ -0,0 +1,57 @@
+package main
+
+import (
+	"blockchain/attacker"
+	"blockchain/config"
+	"blockchain/p2p"
+	"fmt"
+	"math"
+	"math/rand"
+	"time"
+)
+
+func main() {
+	cfg := &config.Default
+	numNodes := cfg.Sim.NumNodes
+	hashDelay := cfg.Sim.HashDelay
+
+	expectedBlock := time.Duration(float64(hashDelay) * math.Pow(16, float64(cfg.Chain.Difficulty)) / float64(numNodes))
+	cfg.P2P.NetDelay = expectedBlock / 300
+
+	fmt.Printf("Starting honest network: %d nodes, difficulty=%d\n", numNodes, cfg.Chain.Difficulty)
+
+	// 1. Start honest network
+	stop := make(chan struct{})
+	nodes := make([]*p2p.Node, numNodes)
+	for i := range nodes {
+		nodes[i] = p2p.NewNode()
+		nodes[i].HashDelay = hashDelay
+		for _, j := range rand.Perm(i)[:min(cfg.P2P.OutboundPeers, i)] {
+			nodes[i].AddPeer(nodes[j])
+			nodes[j].AddPeer(nodes[i])
+		}
+		go nodes[i].Run(stop)
+	}
+
+	// Let the network mine a few blocks first
+	fmt.Println("Waiting for network to mine some blocks...")
+	time.Sleep(5 * time.Second)
+
+	// 2. Create attacker node and connect to network
+	evil := attacker.NewNode()
+	evil.HashDelay = hashDelay
+
+	// Connect to a few honest nodes (like joining the network)
+	for _, j := range rand.Perm(len(nodes))[:min(3, len(nodes))] {
+		evil.AddPeer(nodes[j])
+		nodes[j].AddPeer(evil)
+	}
+
+	fmt.Printf("\n[ATTACKER] Joined network as %s\n", evil.ShortID())
+	fmt.Printf("[ATTACKER] Modify attacker/node.go Run() to implement your attack!\n\n")
+
+	go evil.Run(stop)
+
+	// Wait
+	select {}
+}