Fix typo

IPSec -> IPsec

Author: changeworld

articles/security/develop/threat-modeling-tool-authentication.md

@@ -450,7 +450,7 @@ MSAL also maintains a token cache and refreshes tokens for you when they're clos
 | **Applicable Technologies** | Generic, C#, Node.js,  |
 | **Attributes**              | N/A, Gateway choice - Azure IoT Hub |
 | **References**              | N/A, [Azure IoT hub with .NET](../../iot/tutorial-send-telemetry-iot-hub.md?pivots=programming-language-csharp), [Getting Started with IoT hub and Node JS](../../iot/tutorial-send-telemetry-iot-hub.md?pivots=programming-language-nodejs), [Securing IoT with SAS and certificates](../../iot-hub/iot-hub-dev-guide-sas.md), [Git repository](https://github.com/Azure/azure-iot-sdks/) |
-| **Steps** | <ul><li>**Generic:** Authenticate the device using Transport Layer Security (TLS) or IPSec. Infrastructure should support using pre-shared key (PSK) on those devices that cannot handle full asymmetric cryptography. Leverage Microsoft Entra ID, Oauth.</li><li>**C#:** When creating a DeviceClient instance, by default, the Create method creates a DeviceClient instance that uses the AMQP protocol to communicate with IoT Hub. To use the HTTPS protocol, use the override of the Create method that enables you to specify the protocol. If you use the HTTPS protocol, you should also add the `Microsoft.AspNet.WebApi.Client` NuGet package to your project to include the `System.Net.Http.Formatting` namespace.</li></ul>|
+| **Steps** | <ul><li>**Generic:** Authenticate the device using Transport Layer Security (TLS) or IPsec. Infrastructure should support using pre-shared key (PSK) on those devices that cannot handle full asymmetric cryptography. Leverage Microsoft Entra ID, Oauth.</li><li>**C#:** When creating a DeviceClient instance, by default, the Create method creates a DeviceClient instance that uses the AMQP protocol to communicate with IoT Hub. To use the HTTPS protocol, use the override of the Create method that enables you to specify the protocol. If you use the HTTPS protocol, you should also add the `Microsoft.AspNet.WebApi.Client` NuGet package to your project to include the `System.Net.Http.Formatting` namespace.</li></ul>|
 
 ### Example
 ```csharp