package main

import (
  "fmt"
  "crypto/rsa"
  "encoding/pem"
  "crypto/x509"
  "crypto/rand"
  "bytes"
  "golang.org/x/crypto/ssh"
)

func main() {
  key, _ := rsa.GenerateKey(rand.Reader, 2048)
  privatePem := new(bytes.Buffer)
  privateKey := &pem.Block{
    Type:  "RSA PRIVATE KEY",
    Bytes: x509.MarshalPKCS1PrivateKey(key),
  }
  pem.Encode(privatePem, privateKey)
  fmt.Println(privatePem.String())

  pub, _ := ssh.NewPublicKey(&key.PublicKey)
  fmt.Println(string(ssh.MarshalAuthorizedKey(pub)[:]))
}