Need to know what platform to use to build a secure web portal [on hold]


I need to develop a secure portal and host it on the cloud. The data will be very sensitive as it is about agents posting
online some legal cases to be reviewed by lawyers, and also, there will be online payments. It is very important to keep track
of some past data for a certain number of years, so backup/redundancy are important. Also, the number of registered users is anticipated to more 20000+. up-time is very important and also performance as well as fail-over has to avoided (may need load balancing).
Which development platform (WordPress, Joomla, Drupal, .NET etc.) do you recommend for the UI and business logic development?




I would prefer WordPress above others, the most user-friendly of all.

Drupal is more robust and complex compared to wordpress and Joomla.
Both Joomla and drupal requires more technical knowledge compared to wordpress.

Looking to get started quickly with a simple business website or blog? Look no further than WordPress.

If you have high hopes from day one that your site will grow significantly, requiring extensive features and unlimited customizations, take the plunge with Drupal.

Split between those two options, or need something unique like a social network or eCommerce site, Joomla might be the best bet.

And finally coming .net the security is really high but its the most confusing and complex of all.

WordPress (Best for Beginners) :
1 : Easy to Install
2 : Customizable
3 : Community Support
4 : Plugins can be used for high security

Drupal (More Robust & Complex) :
1 : Technically Advanced
2 : Improved Performance
3 : Customizable

Joomla (Somewhere Between WordPress & Drupal) :
1 : Social Networking
2 : Commerce Sites
3 : Not too Technical
4 : Help Portal



Thanks a lot for your prompt feedback.
In terms of security (passwords hashing/encryption) and performance, WordPress is reliable? we don’t anticipate to have a list of endless customizations, but we are concerned about security (data transfer over the internet to cloud & password encryption etc.), Multilanguage platform, performance, and time-up (as thousands of users would be accessing the portal).
Do you think WordPress can handle all that? or those have nothing to do with it but with hosting and ISP?