# Is using a GUID for an uploaded filename secure?

**URL:** <https://meta.discourse.org/t/is-using-a-guid-for-an-uploaded-filename-secure/67062>\
**Category:** Development\
**Created:** [Julho 29, 2017, 11:53am UTC](https://meta.discourse.org/t/is-using-a-guid-for-an-uploaded-filename-secure/67062 "2017-07-29T11:53:48Z")\
**Posts on this page:** 1\
**Showing post:** 1

<div class="post-metadata">

**Author:** ![rriemann](https://sea3.discourse-cdn.com/meta/user_avatar/meta.discourse.org/rriemann/32/115238_2.png) [@rriemann](https://meta.discourse.org/u/rriemann)\
**Post date:** [Julho 29, 2017, 11:53am UTC](https://meta.discourse.org/t/is-using-a-guid-for-an-uploaded-filename-secure/67062/1 "2017-07-29T11:53:48Z")

</div>

Continuing the discussion from [Quick image resizing and markdown image dimensions](https://meta.discourse.org/t/quick-image-resizing-and-markdown-image-dimensions/66812/25):

> [@Quick image resizing and markdown image dimensions](https://meta.discourse.org/t/quick-image-resizing-and-markdown-image-dimensions/66812/25):
>
> It’s impossible to “increase” security. It can exist or not exist. No half state. If you decide to provide security, then public-accessible links are not good choice. If you don’t care - you can use plain numbers and have short links.

I decided that we are already quite off-topic. So let’s discuss notions of security in this thread.

In many applications, security is not black and white, but can indeed have different qualities that may even allow for a quantification.

- A car is more secure if it has airbags. Without airbags, a car is not unsecure in all cases.
- An encrypted PGP communication is more secure if a longer key size has been employed. This is why we updated key lengths from time to time. Interestingly, security may change in time if the assumptions do not hold anymore. Fukoshima is not secure any longer and also plants identical in construction may be less secure nowadays.

Let’s get back to the question of images and file names. One could define a level of security that depends on the number of educated guesses or the probability to find out a secret (e.g. a file name). In this sense, a longer secret (file name) is certainly more secure. I agree that there are cases where it is impossible to guess the secret, e.g. [one time pad](https://en.wikipedia.org/wiki/One-time_pad).

---

_[View the full topic](https://meta.discourse.org/t/is-using-a-guid-for-an-uploaded-filename-secure/67062)._