Confidentiality Through Encryption - Siemens SIMATIC S7-1500 Function Manual

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3.6 Secure Communication
The figure below shows the TLS protocol in the context of communication layers.
Figure 3-6
Secure communication with OPC UA
An OPC UA server is implemented in S7-1500 CPUs as of firmware V2.0. OPC UA Security
also covers authentication, encryption and data integrity with digital X.509 certificates and
also uses a Public Key Infrastructure (PKI). Depending on the requirements placed by the
application, you can select different security levels for the end point security. You will find the
description of the OPC UA server functionality in the section Using the S7-1500 as an
OPC UA server (Page 159).
3.6.2

Confidentiality through encryption

Message encryption is an important element of data security. When encrypted messages are
intercepted by third parties during communication, these potential eavesdroppers cannot
access the information they contain.
There is a wide range of mathematical processes (algorithms) for encrypting messages.
All algorithms process a "key" parameter to encrypt and decrypt messages.
● Algorithm + key + message => encrypted message
● Encrypted message + key + algorithm => (decrypted) message
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TLS protocol in the context of communication layers
Function Manual, 11/2019, A5E03735815-AH
Communication