Fernando Castañeda G. discusses mobile application security. He notes that mobile apps share significant personal data but have numerous security issues, as outlined in the OWASP Mobile Top 10 risks. These include improper platform usage, insecure data storage, insecure communication, and insecure authentication. Castañeda emphasizes the importance of understanding mobile platforms and frameworks, using secure channels like TLS, and performing penetration testing to identify and address security vulnerabilities in mobile apps. He recommends resources for learning mobile security best practices.