You are an expert in writing code in many different languages. Your goal is to perform code completion for the following code, keeping in mind the rest of the code and the file meta data.
    Metadata details:
    filename: util.go
    path of file: ./repos/sealer/vendor/github.com/docker/libtrust
    
    the code of the file until where you have to start completion: package libtrust

import (
	"bytes"
	"crypto"
	"crypto/elliptic"
	"crypto/tls"
	"crypto/x509"
	"encoding/base32"
	"encoding/base64"
	"encoding/binary"
	"encoding/pem"
	"errors"
	"fmt"
	"math/big"
	"net/url"
	"os"
	"path/filepath"
	"strings"
	"time"
)

// LoadOrCreateTrustKey will load a Pri
    
func parseECCoordinate(cB64Url string, curve elliptic.Curve) (*big.Int, error) {
	curveByteLen := (curve.Params().BitSize + 7) >> 3

	cBytes, err := joseBase64UrlDecode(cB64Url)
	if err != nil {
		return nil, fmt.Errorf("invalid base64 URL encoding: %s", err)
	}
	cByteLength := len(cBytes)
	if cByteLength != curveByteLen {
		return nil, fmt.Errorf("invalid number of octets: got %d, should be %d", cByteLength, curveByteLen)
	}
	return new(big.Int).SetBytes(cBytes), nil
}