func phcAtoi(value string, n int) (int, error) {
	if value == "" {
		return n, nil
	}
	return strconv.Atoi(value)
}
phcAtoi returns the number in the string value or n if value is empty.
package kdf
import (
	"encoding/base64"
	"strconv"
	"strings"
	"github.com/pkg/errors"
)
var phcEncoding = base64.RawStdEncoding