jws sign and verify example

jws.go

package main

import(
  "fmt"
  "gopkg.in/square/go-jose.v2"
  "encoding/json"
  "io/ioutil"
  "crypto/ecdsa"
)


func readKey() jose.JSONWebKey {
  body, err := ioutil.ReadFile("key.json")
  if err != nil {
    panic(err)
  }

  var key jose.JSONWebKey
  if err := json.Unmarshal(body, &key); err != nil {
    panic(err)
  }
  return key
}

func sign() string {

  key := readKey()

  options := &jose.SignerOptions{}
  options.WithHeader("url", "http://a.b.c")

  signer, err := jose.NewSigner(jose.SigningKey{Algorithm: jose.ES256, Key: key}, options)
  if err != nil {
    panic(err)
  }

  payload:= `{"iss":"joe","exp":1300819380,"http://example.com/is_root":true}`

  jws, err := signer.Sign([]byte(payload))
	if err != nil {
		fmt.Println(err.Error())
  }


  zz := jws.FullSerialize()
  fmt.Println(zz)
  output, _ := jws.CompactSerialize()
  fmt.Println(output)

  return output
}

func verify(in string) {

  key := readKey()

  jws, err := jose.ParseSigned(in)
  if err != nil {
    panic(err)
  }
  fmt.Println(jws)

  payload := jws.UnsafePayloadWithoutVerification()
  fmt.Println(string(payload[:]))

  for _, signature := range(jws.Signatures) {
    fmt.Println(signature.Header)
    fmt.Println(signature.Unprotected)
    fmt.Println(signature.Protected)
    fmt.Println(signature.Protected.ExtraHeaders)
  }

  fmt.Println(key)

  privateKey := key.Key.(*ecdsa.PrivateKey)
  publicKey := privateKey.PublicKey

  output, err := jws.Verify(&publicKey)
  if err != nil {
    panic(err)
  }
  fmt.Printf(string(output))
}

func main() {
  fmt.Println("test")

  signed := sign()
  verify(signed)
}

key.json

 {
   "kty":"EC",
   "crv":"P-256",
   "x":"f83OJ3D2xF1Bg8vub9tLe1gHMzV76e8Tus9uPHvRVEU",
   "y":"x_FEzRu9m36HLN_tue659LNpXW6pCyStikYjKIWI5a0",
   "d":"jpsQnnGQmL-YBIffH1136cspYG6-0iY7X1fCE9-E9LI"
}