You can store encrypted values in your ASP.NET Core configuration file and seamlessly decrypt the values as you retrieve them. But there are, at least, two issues that you'll need to address.

Security, anyone? Ease of maintenance? <BR><BR>Our web services use TripleDES encrypted connection strings stored in application-specific config files located on locked down network shares.

The Data protection stack in ASP.NET Core provides an easy-to-use cryptographic API for protecting data, including the necessary mechanisms for encryption and decryption.

Take advantage of connection resiliency in EF Core to detect errors and retry commands and enable your ASP.NET Core application to overcome transient faults.