List of abbreviations

Abbreviation

Description

DMZ

Demilitarized Zone (referred to a perimeter network)

GUI

Graphical User Interface

HTTPS

Hyper Text Transfer Protocol Secure

IoT

Internet of things

IoT2040

MindConnect IoT2040

IP

Internet Protocol

LAN

Local Area Network

MCN

MindConnect Nano

MSU

MindSphere Unit

NAPT

Network Address and Port Translation

OEM

Original Equipment Manufacturer

OPC UA

Open Platform Communications Unified Architecture

PC

Personal Computer

S7

STEP 7

UI

User Interface

The following are the security principles of MindConnect services:

  • Communication between devices and MindSphere cloud services through HTTPS and signed URLs.

  • Authentication and authorisation using OAuth 2.0 mechanisms.

  • Security tokens have a limited timespan of validity and must be renewed.

  • Before installation, firmware is signed and signature is validated by the device.

Onboarding agent (example, MindConnect Nano)

To onboard an agent, establish the trust between agent and MindSphere agent management:

  1. Create an agent in Asset Manager.

  2. Define the network and security profile in Asset Manager.

  3. Download the initial access token and network configuration to your local machine.

  4. Deploy the initial access token to agent, for example via USB stick.

With the initial access token, the agent can prove it‘s identity towards MindSphere agent management by:

  • The Initial Access Token (IAT) is physically entitled to onboard the agent.

  • The initial access token is valid for 7 days for security measures to avoid the misuse.

Registering an agent (example, MindConnect Nano)

To register an agent at agent management, follow these OAuth 2.0 protocol in two cases:

Case-1: Compute limited agent will use a shared secret in further communication. For example, the agent registers at MindSphere agent management with the IAT.
Case-2: Powerfull agent uses public / private keys in further communication. For example, the agent registers at MindSphere agent management with the IAT and additionally, a JSON Web-Key is set according to RFC7517 that contains a self generated public key.

Accepting the registration (example, MindConnect Nano)

With this response, the agent is onboarded and agent management accepts the registration. There are two cases, the agent managmement responds with:

Case 1

  • The shared secret (valid for 7 days) – to be used to access token in the request.

  • The re-registration access token (RAT) – to be used for the renewal of registration, once the registration is expired.

Case 2

  • The re-registration access token (RAT) – to be used for the renewal of registration, once the registration is expired.

  • The agent management stores the public key received after registering an agent and uses it to verify the request access token from agent, which uses JWT signed with private key from now on. For more information, see Onboarding an Agent.

Validity of the credentials

By default, each registered agent (either RSA 3072 or Shared Secret security profile) has its own credentials valid for 7 days and it must be renewed on a regular basis. After this period, MindSphere will not grant any access tokens to the agent and the agent credentials will be invalid. The agent needs to re-register to MindSphere by providing its Registration Access Token (RAT).

Registration access tokens have no practical expiration times but each time a client refreshes its registration a new RAT is generated by MindSphere.

API communication agent (e.g. MindConnect Nano)

Except the one for onboarding and registration, all MindSphere APIs require an access token:

The Agent requests an access token from Agent IAM using a self signed JSON Web Token (JWT). The JWT is signed (see RFC-7515) with either the shared secret (Case 1) or the private key of the public / private key pair (Case 2) in Step 2. The JWT contains the tenantId

The granted access token is valid for 30 minutes. It is also a JWT and contains:

  • tenantId

  • scopes: It describes the type of services used in this token holder.

After expiry, a new token needs to be requested.

Firmware management

Firmware management is stored in secure cloud storage. Agent accesses secure storage through a signed URL issued by MindSphere and it is valid for 7 days.

Firmware is signed with private key from MindSphere. Firmware installer (MERS) on device, checks signature against matching public key provided at initial installation in the factory.

143662324875.png