PHP4 Vs PHP5

You probably know that PHP 5 is destined for OOP, but it appears that habitual programming can be used too. Moreover, OOP is used in PHP4 as well, with the difference that in PHP5 things are a little more evaluated. This means that in PHP4 safety modes for classes (public, private) are not accepted. In PHP4 the objects are a kind of structures which accept objects and functions as well, according to OOP. In PHP4 they are useful as well.

If you are used to working with PHP4 you can use PHP5 with no problems because the differences are not significant and the changes were made so that programmers would not be confused. An example would be class builders which, in PHP4 were functions within the classes bearing the same name as the class. In PHP5 it is firstly checked if there is a function (method) __construct (). If it does not exist, check if there is a function (method) which has the same name as the class. This means that even if you are not aware of the latest news in the domain of PHP5, your scripts will function without any problem.

If you want to install PHP4 and PHP5 in parallel, you can set USE indicators, which are different for each version and you can find out a lot of other important pieces of information asking us.

PHP5 Vs PHP6

PHP is actually a set of extensions that are all gathered together in order to make what we currently have. Nevertheless, these extensions can be changed and the same happens to the collection. Let’s imagine, for example the XML Writer extension. It is a very good extension for writing XML files. A similar extension, XML Reader, has already been attached and allowed in the essential distribution in PHP 5.1, and currently XML Writer will use its model in PHP 6, making an excellent couple in order to work easily with XML files.

Another modification in the essential distribution is the exclusion of the ereg frequent expressions library that is going to become an extension. ereg is now used as a competitor of PCRE (preg_match, etc.), but it seems to cause some problems. Consequently, the experts have made the decision to take it out of the core and change it into an extension.

Now, media type detection is not quite good in PHP. There is mime_magic extension, which is not quite useful. Therefore in PHP 6, the Fileinfo extension will replace mime_magic and it will be integrated in the core while mime_magic will be taken out of the core and changed into extension.

These changes seem to be really interesting. You can conclude that PHP 6 is not really a huge characteristics upgrade, but it is more a great cleanup based on optimizing a lot of functions which already exist, on the move. There are professionals working with PHP almost every day and they can notice improvements every moment.

Symmetric vs. asymmetric algorithms

When using symmetric algorithms, both parties share the same key for en- and decryption. To provide privacy, this key needs to be kept secret. Once somebody else gets to know the key, it is not safe any more. Symmetric algorithms have the advantage of not consuming too much computing power. A few well-known examples are: DES, Triple-DES (3DES), IDEA, CAST5, BLOWFISH, TWOFISH.

Asymmetric algorithms use pairs of keys. One is used for encryption and the other one for decryption. The decryption key is typically kept secretly, therefore called ``private key'' or ``secret key'', while the encryption key is spread to all who might want to send encrypted messages, therefore called ``public key''. Everybody having the public key is able to send encrypted messages to the owner of the secret key. The secret key can't be reconstructed from the public key. The idea of asymmetric algorithms was first published 1976 by Diffie and Hellmann.

Asymmetric algorithms seem to be ideally suited for real-world use: As the secret key does not have to be shared, the risk of getting known is much smaller. Every user only needs to keep one secret key in secrecy and a collection of public keys, that only need to be protected against being changed. With symmetric keys, every pair of users would need to have an own shared secret key. Well-known asymmetric algorithms are RSA, DSA, ELGAMAL.

However, asymmetric algorithms are much slower than symmetric ones. Therefore, in many applications, a combination of both is being used. The asymmetric keys are used for authentication and after this has been successfully done, one or more symmetric keys are generated and exchanged using the asymmetric encryption. This way the advantages of both algorithms can be used. Typical examples of this procedure are the RSA/IDEA combination of PGP2 or the DSA/BLOWFISH used by GnuPG.

in reference to:

"Symmetric vs. asymmetric algorithms When using symmetric algorithms, both parties share the same key for en- and decryption. To provide privacy, this key needs to be kept secret. Once somebody else gets to know the key, it is not safe any more. Symmetric algorithms have the advantage of not consuming too much computing power. A few well-known examples are: DES, Triple-DES (3DES), IDEA, CAST5, BLOWFISH, TWOFISH. Asymmetric algorithms use pairs of keys. One is used for encryption and the other one for decryption. The decryption key is typically kept secretly, therefore called ``private key'' or ``secret key'', while the encryption key is spread to all who might want to send encrypted messages, therefore called ``public key''. Everybody having the public key is able to send encrypted messages to the owner of the secret key. The secret key can't be reconstructed from the public key. The idea of asymmetric algorithms was first published 1976 by Diffie and Hellmann. Asymmetric algorithms seem to be ideally suited for real-world use: As the secret key does not have to be shared, the risk of getting known is much smaller. Every user only needs to keep one secret key in secrecy and a collection of public keys, that only need to be protected against being changed. With symmetric keys, every pair of users would need to have an own shared secret key. Well-known asymmetric algorithms are RSA, DSA, ELGAMAL. However, asymmetric algorithms are much slower than symmetric ones. Therefore, in many applications, a combination of both is being used. The asymmetric keys are used for authentication and after this has been successfully done, one or more symmetric keys are generated and exchanged using the asymmetric encryption. This way the advantages of both algorithms can be used. Typical examples of this procedure are the RSA/IDEA combination of PGP2 or the DSA/BLOWFISH used by GnuPG."
- Symmetric vs. asymmetric algorithms (view on Google Sidewiki)

An Introduction to Microsoft SharePoint Portal Server

As the volume of intranet content grows, administrators and users are increasingly looking for ways to manage the volume of information. Just as Netscape aggregated the then-growing internet content into a manageable framework (called a portal), application vendors have created many packages that allow their customers to aggregate their intranet content into corporate portals.

This series of articles will discuss Microsoft's portal product — SharePoint Portal Server. I hope to provide some value to the readers of Intranet Journal regarding the capabilities (and limitations) of SharePoint. Your feedback is encouraged, and will help me to cover topics that you find relevant.

Introduction to SharePoint

Like most portal products, SharePoint allows visitors to create custom views of the Web site. This customization can be very simple or very complex, depending on the type and version of the product that is installed. In addition, SharePoint has a powerful collaboration model that is tightly integrated with the Office 2003 suite.

The current version of SharePoint is its third (despite its name). Like most Microsoft software, (Windows in particular) version 3 is gaining rapid adoption. A recent article in The Register indicated that SharePoint Portal Server is Microsoft's fastest growing product, with 30 million licenses.

History of SharePoint

Microsoft's first portal application was called Digital Dashboard. This product introduced the concept of Web parts — boxes of information on a page that represented a summary or overview of information. (Other vendors referred to these items as "portlets.") By assembling multiple parts on a page, each user could customize his view of the portal to contain the information that pertained to them. In theory, every visitor of the site could have different content at the same URL. However, the technology behind the Digital Dashboard was not up to the task, and it never made it out of the beta stage.

At the same time, Microsoft's Office group was working toward a collaboration solution. The need for many people to contribute to a single document or worksheet was growing. And, these people were not necessarily working at the same location. The result was SharePoint Team Services (STS), a Web-based solution that allowed shared access to information and documents. STS also allowed end-users to make changes to the site via a Web browser instead of requiring a development-oriented application.

The merging of the collaboration and aggregation functions lead to SharePoint Portal Server 2001. Portal Server has been upgraded to run on the .Net framework and is now referred to as SharePoint Products and Technologies. The "Product" is SharePoint Portal Server 2003 (SPS) and the "Technologies" are Windows SharePoint Services (WSS). A significant point about these two is that WSS is included with the Windows Server 2003 license. Any organization that is licensed for Windows Server 2003 can also host Websites that are based on WSS.

Features of SharePoint

In general, SharePoint contains all of the features you would expect from a portal or collaboration tool:

• Browser-based customization of page
• Browser-based content administration
• Aggregation capabilities
• Document Repository
• Message board
• Ad-hoc data storage
• E-mail notifications
• Announcements, event calendar and contact list.

A complete feature matrix that also indicates whether the feature is part of WSS or SPS can be found in the whitepaper Implementing Rich Collaboration Infrastructure Using Windows SharePoint Services and SharePoint Portal Server 2003 on Microsoft's Web site (http://www.microsoft.com/sharepoint/evaluationoverview.asp).

Uses for SharePoint

In addition to being the default intranet portal, there are many additional uses for SharePoint. Microsoft has included pre-defined templates for Web sites to facilitate meetings, manage projects and create documents. Combined with the "self-service" site creating feature, teams can create and use a Web site with minimal assistance from the Information Technology department.

The Document Workspace template will allow a group to work on a document. The template combines a document repository with a task list and a links list. While using Word 2003, a user can have the document open and at the same time view the task or links list. Changes made to the task list are immediately visible to site visitors. And the document library allows versioning, so edits are not lost.

The Meeting Workspace template combines the agenda, attendee list and Outlook's calendar function. When sending a meeting request in Outlook 2003, a user can create a workspace on the server. The URL of the workspace is automatically included in the message and the attendees are added to the site. The materials required for the meeting can be centrally located, which is preferable for attendees who travel frequently.

The browser-based customization feature, combined with the ability to create ad-hoc lists allows an advanced user to create a site for almost any purpose. A user group could host its meeting schedule, complete handouts. A youth sport organization can post its schedule and roster. An individual can host a blog. The possibilities are endless.

About this series
This series of articles on SharePoint is intended to help you understand the capabilities of the product, as well as provide tips and tricks, development ideas, information from Microsoft, information from the community, and perhaps some samples. Like many other series on IntranetJournal.com, I plan to include how-to articles that can help you with your deployments — ways to customize a page; deployment scenarios; content management; etc. With such a diverse product, there is no lack of topics for this series of articles. What would you like to read?

About the author
Paul Schaeflein is a developer with over twenty years experience. Paul has been developing dynamic and interactive Web sites since 1996. Paul has worked on all of the versions of SharePoint and has worked with the .Net framework since its debut. You can reach Paul through his blog at http://www.schaeflein.net/blog/.