Currently, telecommunications and especially mobile communications have taken great importance and relevance in people's daily activities. However, the use of mobile devices has been threatened by the growing wave of attacks and Trojans as malware (e.g., exploits) for information theft, and fire damage; To mitigate these attacks there are data encryption techniques and authentication processes. In this way, a breach of confidentiality and authenticity in communications can be avoided. On the other hand, some of the existing encryption algorithms are insecure and may require high computational costs. This work analyzes the performance of three of the main encryption algorithms defined by the National Institute of Standards and Technology (NIST): Rijndael as Advanced Encryption Standard (AES), Serpent and Twofish, specifying their main operating characteristics, analyzing performance tests on smart devices, to determine which of these algorithms is the most appropriate to be implemented in each device. Finally, an equation called computational cost is generated, which is a function of RAM, CPU, and battery drain; that analyses for symmetries encryption algorithms that can be performed on similar devices to those treated in this experiment.