Duplicate Guid

[Mark Rance]

Re: Duplicate Guid

Willy Denoyette [MVP] wrote:[color=blue]
> "Jay Douglas" <jayREMOVEIFNOT SPAM@squarei.co m> wrote in message
> news:%23gGYnk4Z FHA.4068@TK2MSF TNGP10.phx.gbl. ..
>[color=green]
>>I thought that MS stopped using the MAC address to create the guids since
>>the cheaper NIC cards were producing duplicate MAC addresses at an alarming
>>rate.
>>
>>--
>>Jay Douglas
>>http://jaydouglas.com
>>
>>[/color]
>
>
> That's right, microsoft doesn't use the DCE algorithm on NT based systems
> (since NT4 SP4), but the reason was a bit of "privacy paranoia", people
> didn't like to give away their MAC addresses through a GUID.
>
> Willy.
>
>[/color]

Is the algorithm MS uses to create a GUID published somewhere?

-Mark

[Willy Denoyette [MVP]]

Re: Duplicate Guid


"Mark Rance" <spamFree@nomai l.com> wrote in message
news:z7adncvMfb BIbzzfRVn-3A@pcisys.net.. .[color=blue]
> Willy Denoyette [MVP] wrote:[color=green]
>> "Jay Douglas" <jayREMOVEIFNOT SPAM@squarei.co m> wrote in message
>> news:%23gGYnk4Z FHA.4068@TK2MSF TNGP10.phx.gbl. ..
>>[color=darkred]
>>>I thought that MS stopped using the MAC address to create the guids since
>>>the cheaper NIC cards were producing duplicate MAC addresses at an
>>>alarming rate.
>>>
>>>--
>>>Jay Douglas
>>>http://jaydouglas.com
>>>
>>>[/color]
>>
>>
>> That's right, microsoft doesn't use the DCE algorithm on NT based systems
>> (since NT4 SP4), but the reason was a bit of "privacy paranoia", people
>> didn't like to give away their MAC addresses through a GUID.
>>
>> Willy.
>>
>>[/color]
>
> Is the algorithm MS uses to create a GUID published somewhere?
>
> -Mark[/color]

..NET uses RNGCryptoServic eProvider which is a wrapper over the cryptographic
pseudorandom number generator inside CryptoAPI which in turn calls Win32's
API CryptGenRandom( ).Note that COM uses the same Win32 API but now through
CoCreateGuid().
I don't know the exact algorithm used by CryptGenRandom( ) and I don't think
it's a trade secret so I would suggest you to ask MSFT for details by
sending a mail to Brian LaMacchia bal@microsoft.c om

Willy.