ec.go

package main

import (
	"crypto/ecdsa"
	"crypto/elliptic"
	"crypto/rand"
	"crypto/x509"
	"encoding/pem"
	"log"
	"os"
)

const (
	pubfilename  = "gokeypub.pem"
	privfilename = "gokey.pem"
)

func toFile(name string, block *pem.Block) {
	f, err := os.OpenFile(name, os.O_WRONLY|os.O_CREATE, 0600)
	if err != nil {
		log.Fatalf("failed to open priv")
	}

	pem.Encode(f, block)
	f.Close()
}

func main() {
	priv, err := ecdsa.GenerateKey(elliptic.P384(), rand.Reader)
	if err != nil {
		log.Printf("key generation failed: %s")
		os.Exit(1)
	}

	privbytes, _ := x509.MarshalECPrivateKey(priv)
	pubbytes, _ := x509.MarshalPKIXPublicKey(&priv.PublicKey)

	log.Printf("saving public key to %s", pubfilename)
	toFile(pubfilename, &pem.Block{
		Type:  "PUBLIC KEY",
		Bytes: pubbytes,
	})

	log.Printf("saving private key to %s", privfilename)
	toFile(privfilename, &pem.Block{
		Type:  "EC PRIVATE KEY",
		Bytes: privbytes,
	})
}