ecdsa: sign in go, verify in node

generate-keys.sh

openssl ecparam -name prime256v1 -genkey -noout -out private.pem
openssl ec -in private.pem -pubout -out public.pem

sign.go

package main

import (
	"crypto/ecdsa"
	"crypto/rand"
	"crypto/sha256"
	"crypto/x509"
	"encoding/base64"
	"encoding/pem"
	"fmt"
	"log"
	"os"
)

func main() {
	if len(os.Args) != 2 {
		log.Println("usage sign text")
	}

	msg := os.Args[1]

	data, err := os.ReadFile("private.pem")
	if err != nil {
		log.Fatal("failed to reader private key", err)
	}

	block, _ := pem.Decode(data)
	if block == nil {
		log.Fatal("failed to read block from private key")
	}

	privateKey, err := x509.ParseECPrivateKey(block.Bytes)
	if err != nil {
		log.Fatal("failed to parse private key", err)
	}

	hash := sha256.Sum256([]byte(msg))

	sig, err := ecdsa.SignASN1(rand.Reader, privateKey, hash[:])
	if err != nil {
		panic(err)
	}

	signature := base64.StdEncoding.EncodeToString(sig)
	fmt.Println(signature)
}

verify.js

const { createVerify } = require("crypto");
const { readFileSync } = require("fs");

if (process.argv.length !== 4) {
  console.log("usage verify message signature");
  process.exit(2);
}

const message = process.argv[2];
const signature process.argv[3];

const publicKey = readFileSync("public.pem");
const verifier = createVerify("sha256");
verifier.update(message);

const verified = verifier.verify(publicKey, signature, "base64");
console.log(verified);