将base64字符串转换为int以在Go中进行加密使用

I'm trying to do some simple cryptography using golang.

I have an RSA public key in form of base64 encoded modulo and exponent. I want to use that values to instantiate rsa.PublicKey struct.

Converting modulo base64 string to big.Int looks pretty straightforward for me.

Unexpectedly, I had a lot of trouble trying to convert base64 string to simple int (the exponent part of RSA key).

The best thing I've came up with:

package main

import (
        "encoding/base64"
        "fmt"
        "math/big"
)

func main() {
        e_data, _ := base64.RawURLEncoding.DecodeString("AQAB")

        e_big := new(big.Int)
        e_big.SetBytes(e_data)
        e := int(e_big.Int64())

        // Finally I have an int here to use it in rsa.PublicKey struct
        fmt.Println(e)
}

Is there any better, more simple way to convert base64 string to int?