Posted on 2006-05-25
Last Modified: 2010-04-16
How are GUIDs generated?

I mean manually.

How can I make one with pencil and paper?

Or is it not like that?
Question by:knowlton
    LVL 35

    Accepted Solution

    From webopedia:
    GUIDs can be created in a number of ways, but usually they are a combination of a few unique settings based on specific point in time (e.g., an IP address, network MAC address, clock date/time, etc.). has some info on algorithms too.

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    Author Comment


    Does anyone know how C# goes about making a GUID?  I mean, what algortihm does it use?
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    Author Comment

    Oh, and are there such things as UUID...same questions apply.
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    Author Comment


    A Globally Unique Identifier or GUID is a pseudo-random number used in software applications. While each generated GUID is not guaranteed to be unique, the total number of unique keys (2128 or 3.4028×1038) is so large that the possibility of the same number being generated twice is very small.

    GUIDs are used in many pieces of software, including Oracle Database and Novell eDirectory, but the most high-profile GUID implementation may be Microsoft's. Theirs is an implementation of a standard called Universally Unique Identifier (UUID), specified by the Open Software Foundation (OSF).

    Okay, so there are UUIDs.

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