Ngrok ensures the security of applications by employing modern TLS (Transport Layer Security) standards, as highlighted by Arianna Willett, the Senior Director of Security Risk & Trust at the company. Willett has a rich background in building and managing security programs for major corporations such as Twilio, Okta, and Deloitte, bringing her expertise to enhance ngrok's security framework. The focus on modern TLS standards underscores ngrok's commitment to providing cutting-edge security measures, safeguarding applications from potential vulnerabilities, and ensuring secure data transmission across networks. This approach reflects a broader industry trend towards adopting advanced security protocols to protect digital assets.