**2.1 Data collection**

The data collected systematically, investigating safety measures in mobile cellular telephony. The search was conducted in databases such as Google Academic® and Portal de Periódicos Capes. The current research is done in searches to Google Academic®, as described by Creswell [2]:

*It is a free database that provides breadth in the search for literature from various sources, such as theses, abstracts and articles, with the advantage of being able to obtain them in full. The Capes Periodicals portal was chosen because it offers access to articles from our Portuguese repertoire selected from over 15,000 international, national and foreign journals and 126 databases with abstracts of documents in all areas of knowledge (Portal de periódicos capes).*

Researches of the type generally used the collection of data. We also used the documentary research for living moments in question and being researcher already some time on the thematic of computer security, distributed system, operating systems. It allowed to know to find some expected results. Thus, it is pertinent the quote of Chaer, Diniz, and Ribeiro [3] "as the research technique composed by an approximately high number of questions presented in writing to people, having as objective the knowledge of opinions, beliefs, feelings, interests, expectations, experienced situations, etc."
