Algorithm used to encrypt password in sysxlogin

Hi,

Does anyone know which algorithm is being used to encrypt the passwords in the sysxlogins for SQL Server 2000? I've been googling for some time..but I can't seem to find this information. Please help.

Many thanks,

Leona

Laurentiu wrote a really good article on this topic, I hope you will find it useful:

http://blogs.msdn.com/lcris/archive/2007/04/30/sql-server-2005-about-login-password-hashes.aspx

-Raul Garcia

SDE/T

SQL Server Engine

|||

Hi Raul,

Thanks for the link provision. Yeah, I saw this information too after so much googling yesterday and I agree it's good. However, it's a pity it ain't official. I was hoping to find the information from an official source, like the MSDN online docs, knowledge base etc. I'm surprised that I can't seem to locate this information...

Cheers,

Leona

|||

Sometimes we don’t have “officially” documentation because of honest mistakes in the process and the intended documentation doesn’t exist at all, in such cases I encourage everyone to give us the proper feedback and we will open bugs for our BOL and try to get them fixed (not always possible due to resource limitations, and I apologize for that); but in other occasions some parts of a feature are not documented on purpose for good reason: if necessary, we reserve the rights to change the implementation.

As Laurentiu mentioned in his article, previous versions of the algorithm were different, and even opened the possibility for attempting to break the passwords via the case-insensitive hashes (as documented by David Litchfield). If the password algorithm would have been fully documented and supported, we may be still in the need to face the same documented weakness in favor of backwards compatibility (probably with some obscure knob to disable), as some applications may still be using it and we would need to go through the (painful) deprecation process.

On the other hand, we don’t believe in security by obscurity, and whenever we have the opportunity some members of the SQL Server team (and sometimes even former members of the team, kudos to Laurentiu for all his help) like to “unofficially” document some features according to our customers feedback or questions in the forums and/or our msdn blogs or when we believe it is useful information that should be documented, but for some reason is not officially documented.

While information on our blogs is not considered “official”, at least I know Laurentiu and I try to validate it and make sure the information and samples we provide are valid (and hopefully useful) because we are trying to help the SQL Server community.

We really appreciate all your feedback as it helps us to improve.

Thanks a lot,

-Raul Garcia

SDE/T

SQL Server Engine

Algorithm used to encrypt password in sysxlogin

Hi,

Does anyone know which algorithm is being used to encrypt the passwords in the sysxlogins for SQL Server 2000? I've been googling for some time..but I can't seem to find this information. Please help.

Many thanks,

Leona

Laurentiu wrote a really good article on this topic, I hope you will find it useful:

http://blogs.msdn.com/lcris/archive/2007/04/30/sql-server-2005-about-login-password-hashes.aspx

-Raul Garcia

SDE/T

SQL Server Engine

|||

Hi Raul,

Thanks for the link provision. Yeah, I saw this information too after so much googling yesterday and I agree it's good. However, it's a pity it ain't official. I was hoping to find the information from an official source, like the MSDN online docs, knowledge base etc. I'm surprised that I can't seem to locate this information...

Cheers,

Leona

|||

Sometimes we don’t have “officially” documentation because of honest mistakes in the process and the intended documentation doesn’t exist at all, in such cases I encourage everyone to give us the proper feedback and we will open bugs for our BOL and try to get them fixed (not always possible due to resource limitations, and I apologize for that); but in other occasions some parts of a feature are not documented on purpose for good reason: if necessary, we reserve the rights to change the implementation.

As Laurentiu mentioned in his article, previous versions of the algorithm were different, and even opened the possibility for attempting to break the passwords via the case-insensitive hashes (as documented by David Litchfield). If the password algorithm would have been fully documented and supported, we may be still in the need to face the same documented weakness in favor of backwards compatibility (probably with some obscure knob to disable), as some applications may still be using it and we would need to go through the (painful) deprecation process.

On the other hand, we don’t believe in security by obscurity, and whenever we have the opportunity some members of the SQL Server team (and sometimes even former members of the team, kudos to Laurentiu for all his help) like to “unofficially” document some features according to our customers feedback or questions in the forums and/or our msdn blogs or when we believe it is useful information that should be documented, but for some reason is not officially documented.

While information on our blogs is not considered “official”, at least I know Laurentiu and I try to validate it and make sure the information and samples we provide are valid (and hopefully useful) because we are trying to help the SQL Server community.

We really appreciate all your feedback as it helps us to improve.

Thanks a lot,

-Raul Garcia

SDE/T

SQL Server Engine

Algorithm used to determine the number of clusters

Hello.

What kind of criterion is used by MS clustering algorithm to determine the number of clusters when 0 is specified in the algorithm parameters?

The problem is that I find automatically defined cluster number somehow strange, especially when expactation maximization algorithm is used. I tried to "manually" calculate optimal cluster numbers in my models using bayesian information criterion and the one by Akaike and received more understandable results.

Thank you very much in advance.

We do not specifically document the heuristic used in this case. The heuristic is intended for scenarios where users (often new to data mining) don't have specific expectations to be met: it provides a useful guess for these scenarios which are often rather diverse. We would not guarantee that it returns the optimal number of clusters in any given scenario.

Note that even setting the number of clusters explicitly is still an approximation, albeit for different reasons. As Books Online describes it, CLUSTER_COUNT "specifies the approximate number of clusters to be built by the algorithm. If the approximate number of clusters cannot be built from the data, the algorithm builds as many clusters as possible."

For the future, would be it be interesting or useful to have detailed, specified (anbd perhaps) selectable methods for cluster counts, such as those you used yourself?

hth

|||Yes, I think it would be interesting to have specified and selectable methods for automatic cluster selection. The reason is that cluster analysis is often used for unsupervised learning before any other methods are applied. Thus, in the first step little information about the data is available and one is interested in natural grouping or clustering in data. So the question "how many natural clusters exist in data" may be very important not less important than "how is data distributed within each cluster". That's why I think it would be useful to have some impact on algorithm used to answer this question.

Algorithm to populate a table with finite value combinations

I need to populate a table which have 10 columns with four values. Each row should be a different combination of these four values and the columns can be null too. In other words how can I get all the different combinations for the 4 values that can be in 10 buckets. The final result column based on these values will be generated manually.

For example , I have for grades (P,F, WP, WF) and I have 8 terms and two exams. 8 terms and two exams can have any of the above four values. Based on these grades and terms and exams I need to generate a table which wil be used to determine the student final status Pass/Fail.

What will be the best way to do this and how is it possible. Is there a T-SQL or C# program for this.

If I need to submit this in another forum please let me know.

Do you just need some code which generates all the possible combinations? There are quite a few: 4 (scores) ^10 (exams) ~ 1M rows, without considering nulls. Do you plan to score them manually after?

You may want to rather develop some sort of scoring system (P =10,F=1, WP..., W...) and require a certain sum or average to pass

|||Yes. I am trying to get some code/algorithm to do this. The manual part will be assigning the Pass/Fail based on the combinations. Thanks.

Algorithm to encrypt the password into Security directory

Hi,

I need know what algorithm to encrypt the password into Security Directory, if anybody know the name.

Thanks

What is the Security directory you mentioned?

Thanks

Laurentiu

sql

Algorithm needed

We are in the process of converting our existing in-house asp web sites to
Sharepoint. Our existing web site has many PDF's, images, etc. These all
reside on the server in a Folder\file. Since Sharepoint now a database
driven architecture, I was wondering if anyone could assist me with some sor
t
of estimate of how much disk space I will need.
I know that Sharepoint stores images, PDFs, etc as BLOBS in the database. I
have no idea of the algorithm or conversion process used.
We will be using SQLServer 2005 database.
Can anyone help me with a formula or algorithm that I can use to estimate
the size of my database when I convert my text files, pdfs, images to
SQLServer 2005 blob files?
Thanks Tomblob is binary storage
the size stored is the same as the source file.
a 1Mb file will consume 1Mb in the database too.
(+ some bytes for the row information, ids etc... this overhead is small)
"Tom" <Tom@.discussions.microsoft.com> wrote in message
news:C10E3198-693D-4845-B89C-C00578FD6C47@.microsoft.com...
> We are in the process of converting our existing in-house asp web sites
> to
> Sharepoint. Our existing web site has many PDF's, images, etc. These all
> reside on the server in a Folder\file. Since Sharepoint now a database
> driven architecture, I was wondering if anyone could assist me with some
> sort
> of estimate of how much disk space I will need.
> I know that Sharepoint stores images, PDFs, etc as BLOBS in the database.
> I
> have no idea of the algorithm or conversion process used.
> We will be using SQLServer 2005 database.
> Can anyone help me with a formula or algorithm that I can use to estimate
> the size of my database when I convert my text files, pdfs, images to
> SQLServer 2005 blob files?
> Thanks Tom|||Jéjé.
Are you saying the size is the same whether its a File, PDF, or image?
ThanksJéjé
"Jéjé" wrote:

> blob is binary storage
> the size stored is the same as the source file.
> a 1Mb file will consume 1Mb in the database too.
> (+ some bytes for the row information, ids etc... this overhead is small)
>
> "Tom" <Tom@.discussions.microsoft.com> wrote in message
> news:C10E3198-693D-4845-B89C-C00578FD6C47@.microsoft.com...
>
>|||Jj means the size of an image value in the database will be the same size
as the source, plus some overhead. SQL Server doesn't know or care about
the content of data stored in image/varbinary/binary columns.
I don't know much about Sharepoint but I understand the product optionally
has full-text search capability, which can contribute to storage
requirements.
Hope this helps.
Dan Guzman
SQL Server MVP
"Tom" <Tom@.discussions.microsoft.com> wrote in message
news:6CEFCA87-3EA6-4505-BD2B-B4DE26FD75D0@.microsoft.com...[vbcol=seagreen]
> Jj.
> Are you saying the size is the same whether its a File, PDF, or image?
> ThanksJj
>
> "Jj" wrote:
>|||you are right, if you index the content, then there is the indexation
overhead too.
but its the same way if you index the document from the disk or from the
database, the result is the same and the overhead is near the same too.
Maybe sharepoint store more metadata information, but again, the size of
this metadata is small.
and Yes, SQL Server store the content as is, its a byte storage, there is no
compression, no format changes.
so the size of the source file doesn't change.
"Dan Guzman" <guzmanda@.nospam-online.sbcglobal.net> wrote in message
news:OpSh1kxxGHA.3440@.TK2MSFTNGP06.phx.gbl...
> Jj means the size of an image value in the database will be the same
> size as the source, plus some overhead. SQL Server doesn't know or care
> about the content of data stored in image/varbinary/binary columns.
> I don't know much about Sharepoint but I understand the product optionally
> has full-text search capability, which can contribute to storage
> requirements.
> --
> Hope this helps.
> Dan Guzman
> SQL Server MVP
> "Tom" <Tom@.discussions.microsoft.com> wrote in message
> news:6CEFCA87-3EA6-4505-BD2B-B4DE26FD75D0@.microsoft.com...
>

Algorithm needed

We are in the process of converting our existing in-house asp web sites to
Sharepoint. Our existing web site has many PDF's, images, etc. These all
reside on the server in a Folder\file. Since Sharepoint now a database
driven architecture, I was wondering if anyone could assist me with some sort
of estimate of how much disk space I will need.
I know that Sharepoint stores images, PDFs, etc as BLOBS in the database. I
have no idea of the algorithm or conversion process used.
We will be using SQLServer 2005 database.
Can anyone help me with a formula or algorithm that I can use to estimate
the size of my database when I convert my text files, pdfs, images to
SQLServer 2005 blob files?
Thanks Tomblob is binary storage
the size stored is the same as the source file.
a 1Mb file will consume 1Mb in the database too.
(+ some bytes for the row information, ids etc... this overhead is small)
"Tom" <Tom@.discussions.microsoft.com> wrote in message
news:C10E3198-693D-4845-B89C-C00578FD6C47@.microsoft.com...
> We are in the process of converting our existing in-house asp web sites
> to
> Sharepoint. Our existing web site has many PDF's, images, etc. These all
> reside on the server in a Folder\file. Since Sharepoint now a database
> driven architecture, I was wondering if anyone could assist me with some
> sort
> of estimate of how much disk space I will need.
> I know that Sharepoint stores images, PDFs, etc as BLOBS in the database.
> I
> have no idea of the algorithm or conversion process used.
> We will be using SQLServer 2005 database.
> Can anyone help me with a formula or algorithm that I can use to estimate
> the size of my database when I convert my text files, pdfs, images to
> SQLServer 2005 blob files?
> Thanks Tom|||Jéjé.
Are you saying the size is the same whether its a File, PDF, or image?
ThanksJéjé
"Jéjé" wrote:
> blob is binary storage
> the size stored is the same as the source file.
> a 1Mb file will consume 1Mb in the database too.
> (+ some bytes for the row information, ids etc... this overhead is small)
>
> "Tom" <Tom@.discussions.microsoft.com> wrote in message
> news:C10E3198-693D-4845-B89C-C00578FD6C47@.microsoft.com...
> > We are in the process of converting our existing in-house asp web sites
> > to
> > Sharepoint. Our existing web site has many PDF's, images, etc. These all
> > reside on the server in a Folder\file. Since Sharepoint now a database
> > driven architecture, I was wondering if anyone could assist me with some
> > sort
> > of estimate of how much disk space I will need.
> >
> > I know that Sharepoint stores images, PDFs, etc as BLOBS in the database.
> > I
> > have no idea of the algorithm or conversion process used.
> >
> > We will be using SQLServer 2005 database.
> >
> > Can anyone help me with a formula or algorithm that I can use to estimate
> > the size of my database when I convert my text files, pdfs, images to
> > SQLServer 2005 blob files?
> >
> > Thanks Tom
>
>|||Jéjé means the size of an image value in the database will be the same size
as the source, plus some overhead. SQL Server doesn't know or care about
the content of data stored in image/varbinary/binary columns.
I don't know much about Sharepoint but I understand the product optionally
has full-text search capability, which can contribute to storage
requirements.
--
Hope this helps.
Dan Guzman
SQL Server MVP
"Tom" <Tom@.discussions.microsoft.com> wrote in message
news:6CEFCA87-3EA6-4505-BD2B-B4DE26FD75D0@.microsoft.com...
> Jéjé.
> Are you saying the size is the same whether its a File, PDF, or image?
> ThanksJéjé
>
> "Jéjé" wrote:
>> blob is binary storage
>> the size stored is the same as the source file.
>> a 1Mb file will consume 1Mb in the database too.
>> (+ some bytes for the row information, ids etc... this overhead is small)
>>
>> "Tom" <Tom@.discussions.microsoft.com> wrote in message
>> news:C10E3198-693D-4845-B89C-C00578FD6C47@.microsoft.com...
>> > We are in the process of converting our existing in-house asp web sites
>> > to
>> > Sharepoint. Our existing web site has many PDF's, images, etc. These
>> > all
>> > reside on the server in a Folder\file. Since Sharepoint now a database
>> > driven architecture, I was wondering if anyone could assist me with
>> > some
>> > sort
>> > of estimate of how much disk space I will need.
>> >
>> > I know that Sharepoint stores images, PDFs, etc as BLOBS in the
>> > database.
>> > I
>> > have no idea of the algorithm or conversion process used.
>> >
>> > We will be using SQLServer 2005 database.
>> >
>> > Can anyone help me with a formula or algorithm that I can use to
>> > estimate
>> > the size of my database when I convert my text files, pdfs, images to
>> > SQLServer 2005 blob files?
>> >
>> > Thanks Tom
>>|||you are right, if you index the content, then there is the indexation
overhead too.
but its the same way if you index the document from the disk or from the
database, the result is the same and the overhead is near the same too.
Maybe sharepoint store more metadata information, but again, the size of
this metadata is small.
and Yes, SQL Server store the content as is, its a byte storage, there is no
compression, no format changes.
so the size of the source file doesn't change.
"Dan Guzman" <guzmanda@.nospam-online.sbcglobal.net> wrote in message
news:OpSh1kxxGHA.3440@.TK2MSFTNGP06.phx.gbl...
> Jéjé means the size of an image value in the database will be the same
> size as the source, plus some overhead. SQL Server doesn't know or care
> about the content of data stored in image/varbinary/binary columns.
> I don't know much about Sharepoint but I understand the product optionally
> has full-text search capability, which can contribute to storage
> requirements.
> --
> Hope this helps.
> Dan Guzman
> SQL Server MVP
> "Tom" <Tom@.discussions.microsoft.com> wrote in message
> news:6CEFCA87-3EA6-4505-BD2B-B4DE26FD75D0@.microsoft.com...
>> Jéjé.
>> Are you saying the size is the same whether its a File, PDF, or image?
>> ThanksJéjé
>>
>> "Jéjé" wrote:
>> blob is binary storage
>> the size stored is the same as the source file.
>> a 1Mb file will consume 1Mb in the database too.
>> (+ some bytes for the row information, ids etc... this overhead is
>> small)
>>
>> "Tom" <Tom@.discussions.microsoft.com> wrote in message
>> news:C10E3198-693D-4845-B89C-C00578FD6C47@.microsoft.com...
>> > We are in the process of converting our existing in-house asp web
>> > sites
>> > to
>> > Sharepoint. Our existing web site has many PDF's, images, etc. These
>> > all
>> > reside on the server in a Folder\file. Since Sharepoint now a
>> > database
>> > driven architecture, I was wondering if anyone could assist me with
>> > some
>> > sort
>> > of estimate of how much disk space I will need.
>> >
>> > I know that Sharepoint stores images, PDFs, etc as BLOBS in the
>> > database.
>> > I
>> > have no idea of the algorithm or conversion process used.
>> >
>> > We will be using SQLServer 2005 database.
>> >
>> > Can anyone help me with a formula or algorithm that I can use to
>> > estimate
>> > the size of my database when I convert my text files, pdfs, images to
>> > SQLServer 2005 blob files?
>> >
>> > Thanks Tom
>>
>

Algorithm : Data Mining

Hello friends,

Can u give some idea about the Algorithm in Data Mining for Clustering..

Please reply...

The clustering implementation in SQL Server Data Mining supports two clustering methods - standard k-means and EM, which is based on this paper:

Paul S. Bradley; Usama M. Fayyad; Cory A. Reina
Scaling EM (Expectation Maximization) Clustering to Large Databases,
MSR-TR-98-35, 1998
http://www.research.microsoft.com/scripts/pubs/view.asp?TR_ID=MSR-TR-98-35.

Algorithm

Well, i have read in claude seidman book about data mining that some algorithm inside in microsoft decision tree are CART, CHAID and C45 algorithm. could anyone explain to me about the tree algorithm and please explain to me how the tree algorithm used together in one case?

thank you so much

The decision tree algorithm used by MS is not CART, CHAID, or C4.5 - it's an algorithm developed by Microsoft Research.

There's more information available here:

"Scalable Classification over SQL Databases"

ftp://ftp.research.microsoft.com/users/AutoAdmin/icde99.pdf

"Learning Bayesian Networks: The Combination of Knowledge and Statistical Data"

http://research.microsoft.com/research/pubs/view.aspx?tr_id=81

sql