package main

import (
    "encoding/base64"
    "fmt"
)

func encodeB2Key (user_id, app_key string) (string) {

    str := (user_id + ":" + app_key)
    data := []byte(str)
    data = base64.StdEncoding.EncodeToString(data)
    return string(data)
}

func main() {
    b2id := "backblaze_b2_user_id"
    b2key := "backblaze_b2_app_key"
    str := encodeB2Key(b2id, b2key)
    fmt.Println(str)
}