Questions tagged [guid]

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2answers
4k views

Using V4 UUID for authentication

I'd like to use a V4 UUID / GUID for authenticating users. To be specific, the user would have to paste the UUID into a text field to gain access to their account. The UUID would be given to them at ...
2
votes
0answers
152 views

Using a GUID as an authentication token (and how it could be improved)

I'm implementing a Whatsapp Web-like feature for my Android application. User should be able to open an HTTPS web application that displays a QR code (a GUID generated by the server) and scan it using ...
1
vote
2answers
45 views

Purpose of using GUID for files along with underlying permissions checks

Some sites utilize a GUID for a file name when it goes in storage. For example, when you load up a receipt, instead of having the receipt named something like 1200 (an incremental number), it will ...
1
vote
1answer
214 views

Mobile application authentication using UUID

I write back-end code for mobile applications. I am needing to write the code for authentication and the simplest yet secure solution I can think of is: When user signs in, device sends username and ...
0
votes
1answer
18k views

Why does UUID v4 have the format xxxxxxxx-xxxx-4xxx-zxxx-xxxxxxxxxxxx? [closed]

I'm very curious as to why the format is xxxxxxxx-xxxx-4xxx-zxxx-xxxxxxxxxxxx? Why is the 4 there, and why is z always either 8, 9, A, B? And also, why the different string lengths between the dashes? ...
0
votes
1answer
268 views

With a very large number of GUIDs, can one predict the previous and subsequent GUIDs that will be generated?

I've been reading up on GUIDs. According to the Wiki: Cryptanalysis of the WinAPI GUID generator shows that, since the sequence of V4 GUIDs is pseudo-random, given full knowledge of the internal ...
0
votes
2answers
66 views

How to solve the problem of secure randomly generated GUIDs when the size of the data outgrows the GUIDs

I've been struggling with this problem for a little while... How to hide the order that records were created in, basically. You typically do this by generating a "GUID". But this GUID is arbitrarily ...
0
votes
1answer
54 views

Passing user ID as parameter without any authentication, what are the security risks?

I've read that passing GUID as URL parameter isn't considered insecure because usually, an app has an authentication mechanism (checking against some session token). However, how secure would an ...
0
votes
1answer
206 views

Identifying devices in mobile app using UUID

I have a mobile application, for Android and iOS (both native), that communicates with the backend through a REST API (over HTTPS). The application allows users to sign in or use the app as a guest, ...
0
votes
1answer
139 views

Using the user's GUID-id as a salt for Rfc2898DeriveBytes

I use the Rfc2898DeriveBytes for creating an AES key for protecting the user's data. For the salt value I would like to use the user's id, which is a guid. My understanding is, that the only drawback ...
0
votes
1answer
51 views

COM Classes CLSID

Would malware ever create a CLSID or would they just use them? This question is derived from studying COM objects. So an Adobe exploit would have an Adobe CLSID in it. Does malware ever create a CLSID ...
0
votes
0answers
40 views

set-guid exploit of a programm with relativ path

I'm trying to exploit a program which has the set-guid bit enabled. The program is simple it contains the following (stage.c): #include <stdio.h> #include <stdlib.h> #include <unistd....