The OPC Foundation (OPC formally known as Object Linking and Embedding for Process Control) is an industry consortium that creates and maintains standards for open connectivity of industrial automation devices and systems, such as industrial control systems and process control generally. The OPC standards specify the communication of industrial process data, alarms and events, historical data and batch process data betweensensors, instruments, controllers, software systems, and notification devices.

OPC Unified Architecture (OPC UA) is an industrial M2M communication protocol for interoperability developed by the OPC Foundation. It is the successor to Open Platform Communications (OPC). Although developed by the same organization, OPC UA differs significantly from its predecessor. The Foundation's goal for this project was to provide a path forward from the original OPC communications model (namely the Microsoft Windows only process exchange COM/DCOM) to a cross-platform service-oriented architecture (SOA) for process control, while enhancing security and providing an information model.[1]

ioCGW operates as a master device capable to connect sequential to the all in system registered local Weather Stations (WS) operating as slaves. Also, ioCGW is connected to the cloud using WiFi/2G/3G/4G or wired connection to the internet.

In Figure the wireless Radio Frequency (RF) communication system is used using long range 169 MHz radio transceivers is presented. According to ETSI EN 300 220-1 V2.4.1 2012-01 Part 1.169,400 - 169,475 MHz frequency range can be used for tracking, observation and measurements needs.

For wireless communication between ioCGW and WS we offer to use secure method, based on the symmetric cryptography. It ensures the following information security properties:

Confidentiality;

Authenticity ;

Integrity;

Prevention from replay and alternation attacks.

IoT System

https://en.wikipedia.org/wiki/OPC_Unified_Architecture

Cebit 2017: security in IoT <-- EuroNews

Authenticated Encryption

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RF communication system is operating together with STM32L162 series microcontroller having the following functions useful for secure sub-system constructionhttp://www.st.com/st-web-ui/static/active/en/resource/technical/document/datasheet/DM00039232.pdf

AES-128 bit encryption hardware accelerator;•CRC calculation unit;•RTC real-time clock and a set of backup registers that remain powered in Standby mode

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Continuous Counter modulo 256•96-bit unique ID;•

The AES-128 is realized by hardware accelerator using the AES algorithm compatible with FIPS PUB 197, 2001 Nov 26. This algorithm has the following functions:Key scheduler •Key derivation for decryption •128-bit data block processed •128-bit key length •213 clock cycles to encrypt/decrypt one 128-bit block •Electronic codebook (ECB), cypher block chaining (CBC), and counter mode (CTR) supported by hardware.

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To prevent reply attack both RTC and Continuous Counter modulo 256 can be used. These data should be included in encrypted part of data package.

Encrypt-then-authenticate system is CCA-secure.

CCM Protocols represent encrypt-then-authenticate system which is CCA-secure.Encryption-decryption operation will be performed with key k1 using CTR mode. MAC operation must be performed using the different key k2 by NIST approved CBC based MAC algorithm denoted by CMAC, described in (Dworkin, 2001), http://csrc.nist.gov/publications/nistpubs/800-38B/SP_800-38B.pdf

Realization 1. Encrypt-then-authenticate.Protocol 1 consist of two stages: MAC key k2 generation and sharing between parties.1.Encrypted and authenticated data exchange.2.

Realization 2. Authenticated encryption using AES-128 CCM mode of operation.This scheme is not requiring an additional MAC key k2 predistribution, but for authenticity verification it requires data decryption. Hence invalid data packages can not be rejected before decryption operation is carried out.

Six different authenticated encryption modes namely:OCB 3.0, 2011, Offset Codebook Mode

CCM, Counter with CBC-MAC

EAX, 2003, Encrypt-then-MAC (EtM),

GCM Galois/Counter Mode ISO/IEC 19772:2009, (ISO/IEC, 2013): hard to understand

NIST approved authenticated encryption algorithm is based on AES-128 operating in CCM mode, (Dworkin, 2001),

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mode, (Dworkin, 2001),http://csrc.nist.gov/publications/nistpubs/800-38B/SP_800-38B.pdf

Special Publication 800-38C specifies the CCM mode of the AES algorithm. CCM combines the counter (CTR) mode for confidentiality with the cipher block chaining (CBC) technique for authentication. CCM stands for CTR CBC MAC. The specification is intended to be compatible with the use of CCM within a draft amendment to the IEEE 802.11 standard for wireless local area networks.The Special Publications 800-38A, 800-38B and 800-38C are in the list of NIST adopted block cipher modes of operations, see http://csrc.nist.gov/groups/ST/toolkit/BCM/current_modes.html. The more detail information is presented in http://csrc.nist.gov/publications/nistpubs/800-38C/SP800-38C_updated-July20_2007.pdf

CCM is considered as a mode of operation of the block cipher algorithm. As with other modes of operation, a single key to the block cipher must be established beforehand among the parties. Thus, CCM as other symmetric ciphers should be implemented within a well-designed key management structure. The security properties of CCM depend, at a minimum, on the secrecy of the key.CCM is intended for use in a packet environment, i.e., when all of the data is available in storage before CCM is applied; CCM is not designed to support partial processing or stream processing. The input to CCM includes three elements: 1) data that will be both authenticated and encrypted, called the payload; 2) associated data, e.g., a header, that will be authenticated but not encrypted; and 3) a unique value, called a nonce, that is assigned to the payload and the associated data.

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