foo.go

package main

import (
	"crypto/md5"
	"fmt"
	"io/ioutil"

	"code.google.com/p/go.crypto/ssh"
)

func main() {
	b, err := ioutil.ReadFile("/tmp/id_rsa2.pub")
	if err != nil {
		panic(err)
	}

	fmt.Println(string(b))

	pubkey, err := ssh.ParsePublicKey(b)
	if err != nil {
		panic(err)
	}

	fmt.Printf("%x", md5.Sum(pubkey.Marshal()))
}