Installable cloud apps deployed from PowerServer 2021 adopt standard cloud-native architecture running on the .NET framework and adhere to industry best practices for security. All SQLs and DataWindows execute behind the firewall. Data is accessed through industry-standard REST APIs, secured by OAuth or JWT. The client app is encrypted, digitally signed and checked for integrity. 

For more information, refer to Whitepaper: PowerServer 2021 Security Measures.