Pauls Blog

https://weblogs.asp.net/jongalloway/encrypting-passwords-in-a-net-app-config-file This page uses: System.Runtime.InteropServices.Marshal.SecureStringToBSTR System.Runtime.InteropServices.Marshal.PtrToStringBSTR System.Runtime.InteropServices.Marshal.ZeroFreeBSTR System.Security.Cryptography.ProtectedData.Unprotect System.Security.Cryptography.ProtectedData.Protect System.Security.Cryptography.DataProtectionScope.CurrentUser

You can access key value pairs within appSettings with AppSettingsReader An example is available at  https://docs.microsoft.com/en-us/dotnet/api/system.configuration.appsettingsreader?view=netframework-4.7.1