ASP: simple CAPTCHA method

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I'm sure you know what CAPTCHAs are. They usually are not very welcomed when filling in a form, but the idea behind them is to at least reduce the possibility of automatic non-human procedures submitting the form itself. The main point is to recognise if who or what is submitting a request is really a human or not.

The solution I'm presenting here is very simple and it is not unbreakable. Infact, today we surely need a highly sophisticated CAPTCHA procedure in order to be completely sure of its effectiveness.
On the other hand, we can use the solution here presented whenever we need a little bit more security.
We are going to use ASP and GUIDs (Globally Unique Identifier).

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SQL Server: use the NewId() function to create unique identifiers

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A few months ago, I have published an article mentioning the NewId() SQL function. In that post, I was explaining how to create dynamic keywords and description meta tags. However the NewId() function can be used in different situations and it becomes very handy, when we need unique identifiers.
Let's see how it works.

The basics

The NewId() function returns a unique identifier; that means a unique set of numbers and letters. If we use the function in a query in SQL Server Management Studio like:

print newid()

the result will be a unique identifier like:

5C6C9372-49F9-4A5C-BCFA-DA6CDB525CAB

Interestingly enough, the above result is unique and can be used in various way. For example, we can use the function to generate personal identification numbers (PINs), login passwords, ids, serial numbers or product keys, simple primary keys etc. At the same time we can use the function to create random sorting of data.