package main

import (
    "encoding/asn1"
    "fmt"
    "math/big"
)

func main() {
    data := &struct {
        A int64
        B *big.Int
    }{}
    _, err := asn1.Unmarshal([]byte{0x30, 0x0e, 0x02, 0x05, 0x00, 0x00, 0x00, 0x00, 0x02, 0x02, 0x05, 0x00, 0x00, 0x00, 0x00, 0x01}, data)
    if err != nil {
        panic(err)
    }
    fmt.Printf("%#v\n", data)
}