This project starts off with giving an overview of what sensitive data is, encryption algorithms and other required knowledge for this thesis project.This is because of the aim of this thesis project, that is to find the best way to encrypt data passed through a URL with a focus on protecting sensitive data in web applications. Data sent through the URL of a web application could be sensitive data, and exposure of sensitive data can be devastating for governments, companies, and individuals. The tools and methods that are used for this thesis project are described. An overview is given of the requirements of the web application that was to be created, the development of it, implementation and comparison of encryption algorithms. After that, the results of the encryption algorithms are compared and displayed together with a prototype of the web application and its encryption. The results are then analyzed in two different sections: security of the encryptions and performance tests. With the results given we conclude which one of the encryption algorithms is the most suitable for our web application, and otherwise when encrypting data through the URL of a web application. The results show that AES has a great advantage over 3DES both in security and performance when encrypting sensitive data passed through a URL.Those results are then used to build a secure web application to help and assist a broker during an open showing. The web application is then used together with information from interested buyers so it can be easy for the broker to contact them after the showing.