# Can GUIDs be duplicate?

## Can GUIDs be duplicate?

How unique is a GUID? 128-bits is big enough and the generation algorithm is unique enough that if 1,000,000,000 GUIDs per second were generated for 1 year the probability of a duplicate would be only 50%. Or if every human on Earth generated 600,000,000 GUIDs there would only be a 50% probability of a duplicate.

### What is the probability of two GUIDs being the same?

GUID generation algorithm 4 fills the GUID with 122 random bits. The odds of two GUIDs colliding are therefore one in 2¹²², which is a phenomenally small number.

How do you generate unique GUIDs?

To Generate a GUID in Windows 10 with PowerShell, Type or copy-paste the following command: [guid]::NewGuid() . This will produce a new GUID in the output. Alternatively, you can run the command ‘{‘+[guid]::NewGuid(). ToString()+’}’ to get a new GUID in the traditional Registry format.

Can UUID be duplicate?

While the probability that a UUID will be duplicated is not zero, it is close enough to zero to be negligible. Thus, anyone can create a UUID and use it to identify something with near certainty that the identifier does not duplicate one that has already been, or will be, created to identify something else.

## Can 2 UUID be the same?

A UUID is just a 128-bit random number. When my computer generates a UUID, there’s no practical way it can prevent your computer or any other device in the universe from generating that same UUID at some time in the future. It may not be likely that any two UUIDs will be the same, but they can be.

### How are GUIDs generated?

Basically, a a GUID is generated using a combination of: The MAC address of the machine used to generate the GUID (so GUIDs generated on different machines are unique unless MAC addresses are re-used) Timestamp (so GUIDs generated at different times on the same machine are unique)

Can GUIDs be predicted?

Predicting the next GUID would be unreliable even if you could do it, but more than likely is completely impossible with the resources at your disposal.

For example, one person wondered whether it was okay to use the first eight characters of a GUID as a temporary account password. This is a really bad idea. GUIDs are designed for uniqueness, not for security.

## How hard is it to guess a UUID?

GUIDs are guaranteed to be unique and that’s about it. Not guaranteed to be be random or difficult to guess.

### Is it possible to duplicate a UUID?

I speculate that, theoretically, you have a better chance of duplicating a UUID across multiple systems, than on a single system. While the OS isn’t going to store each GUID that it generates, it probably uses some time based seed data to avoid collisions in itself. Of course this is dependent on the implementation.

Can I generate 2 GUID’s at the same time?

Show activity on this post. A GUID (globally unique identifier) is a 32 character hexadecimal string: If you randomly generate 2, the chance of them being the same is incredibly small.

What is the GUID and where is it stored?

The GUID is stored in the client’s Registry and in a binary file on the client’s hard disk. Many problems in an SMS 2003 environment may occur if more than one SMS 2003 client has the same GUID. The whole site may even be disabled.

## Do the globally unique identifiers have any chance of duplicates?

There is always some miniscule chance of duplicates, but Globally Unique Identifiers are meant to be just that: globally unique …not system-wide unique, but as in the Planet Earth unique.