package main

import (
  "log"
  "crypto/rand"
  "crypto/rsa"
  "golang.org/x/crypto/ssh"
)

func main() {
  certPrivateKey, err := rsa.GenerateKey(rand.Reader, 512)
  if err != nil {
    log.Fatalf("Error generating cert key: %v", err)
  }

  certPublicKey, err := ssh.NewPublicKey(&certPrivateKey.PublicKey)
  if err != nil {
     log.Fatalf("Error generating ssh public key: %v", err)
  }

  cert := &ssh.Certificate{
    Key:             certPublicKey,
    CertType:        1,
    KeyId:           "{requester: \"bob\"}",
    ValidPrincipals: []string{"alice"},
  }

  signer, err := ssh.NewSignerFromKey(certPrivateKey)
  if err != nil {
     log.Fatalf("Error creating signer: %v", err)
  }

  err = cert.SignCert(rand.Reader, signer)
  if err != nil {
     log.Fatalf("Error signing certificate: %v", err)
  }

  marshaled := cert.Marshal()

  parsedCert := &ssh.Certificate{}

  err = ssh.Unmarshal(marshaled, parsedCert)
  if err != nil {
     log.Fatalf("error unmaarshaling: %v", err)
  }

  if err != nil {
     log.Fatalf("error parsing cert: %v", err)
  }

  if parsedCert.CertType != cert.CertType {
     log.Fatalf("Error, parsed certType did not match %s", cert.CertType)
  }

}