Continuing the discussion from Quick image resizing and markdown image dimensions : [image] Quick image resizing and markdown image dimensions 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 …

Or… you can just use global incrementing counter and short natural numbers. Sorry, if that sounds stupid, i’m not familiar with reasons why guid-s were selected for attachments (i know all advantages and disadvandages, but don’t know what is more important for discourse).

I believe that attachments don’t have any validation on them when you request them, so with an incremental id, you could easily guess and retrieve attachments from topics and pms that you otherwise can’t access.

“security by obscurity” is not safe approach. For example, if someone index email content of notifications about new messages… people can suddenly find you secrets in image search.

Let’s consider this scenario: The whole must-register forum with 1k people uses mailing list mode and somebody creates a post with few photos. I do not see another mean to protect the photos in the forum while still making them accessible from within mail viewers than using random filenames. I’m no…

[image] Quick image resizing and markdown image dimensions I do not see another mean to protect the photos in the forum while still making them accessible from within mail viewers than using random filenames. In this case you could prepare different content for email and for thread. For exampl…

[image] Quick image resizing and markdown image dimensions For example, email can have embedded images (not public accessible link). People discussed the idea to send out only PGP encrypted mails. If this idea would be implemented, I agree that it would be nice to also increase the security fo…

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. There are cases, when guid-s are useful - for parallel clustered …

[image] fefrei: Both models hinge on the assumption that some string is not guessed. No. Link with public access will be shared in unpredictable ways. You can not provide security at this step. So, you can not rely on assumption that your “secret link” will be secret forever, this can go out …

You cannot protect against that: The file itself could be shared just as unpredictably as the link. You have to assume that users won’t share the file with the attacker; why would you assume that these links are more likely to be shared?

Is using a GUID for an uploaded filename secure?

Development

fefrei (Felix Freiberger) Juillet 29, 2017, 11:41 9

Why do you think that an unguessable download link is less secure than requiring password authentication for the download? Both models hinge on the assumption that some string is not guessed.

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Is using a GUID for an uploaded filename secure?

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