use sha256sum as private key

govanity.diff

diff --git a/generate.go b/generate.go
index 6fa11d6..9cff58f 100644
--- a/generate.go
+++ b/generate.go
@@ -2,8 +2,10 @@ package main
 
 import (
 	"crypto/rand"
+	"crypto/sha256"
 	"flag"
 	"fmt"
+	"io/ioutil"
 	"math/big"
 	"os"
 	"strings"
@@ -20,6 +22,7 @@ func main() {
 
 	var prefix string
 	flag.StringVar(&prefix, "prefix", "123", "prefix you want for your vanity address")
+	fn := flag.String("f", "generate.go", "target filename")
 	flag.Parse()
 
 	fmt.Printf("Searching for prefix \"%s\"\n", prefix)
@@ -33,6 +36,15 @@ func main() {
 		fmt.Printf("failed to read seed data: %s\n", err)
 		os.Exit(1)
 	}
+	if fn != nil {
+		body, err := ioutil.ReadFile(*fn)
+		if err != nil {
+			fmt.Printf("failed to read data: %s\n", err)
+			os.Exit(1)
+		}
+		r := sha256.Sum256(body)
+		copy(seed, r[:])
+	}
 
 	var numFound int
 	var x, y *big.Int
@@ -63,7 +75,7 @@ func main() {
 		// Encode the address and check the prefix.
 		addr := base58.CheckEncode(btcutil.Hash160(serialized[:]),
 			net.PubKeyHashAddrID)
-		if strings.HasPrefix(addr, prefix) {
+		if fn != nil || strings.HasPrefix(addr, prefix) {
 			privkey, _ := btcec.PrivKeyFromBytes(s256, seed)
 			wif, err := btcutil.NewWIF(privkey, net, false)
 			if err != nil {
@@ -74,6 +86,9 @@ func main() {
 			fmt.Printf("\nElapsed: %s\naddr: %s\nwif: %s\nnumfound: %d\n",
 				time.Since(beginTime), addr, wif.String(),
 				numFound)
+			if fn != nil {
+				break
+			}
 		}
 
 		seed[0]--

https://github.com/jimmysong/govanity

for Monacoin

@@ -13,6 +15,7 @@ import (
 	"github.com/btcsuite/btcd/chaincfg"
 	"github.com/btcsuite/btcutil"
 	"github.com/btcsuite/btcutil/base58"
+	monacfg "github.com/wakiyamap/monad/chaincfg"
 )
 
 func main() {
@@ -20,12 +23,15 @@ func main() {
 
 	var prefix string
 	flag.StringVar(&prefix, "prefix", "123", "prefix you want for your vanity address")
+	fn := flag.String("f", "generate.go", "target filename")
 	flag.Parse()
 
 	fmt.Printf("Searching for prefix \"%s\"\n", prefix)
 
 	s256 := btcec.S256()
 	net := &chaincfg.MainNetParams
+	monanet := &monacfg.MainNetParams
+	net.PubKeyHashAddrID = monanet.PubKeyHashAddrID