Cybersecurity Fundamentals
Expert-defined terms from the Professional Certificate in Operational Technology Engineer (United Kingdom) course at LearnUNI. Free to read, free to share, paired with a professional course.
Access Control – mechanisms that restrict who can view or use resources #
Related terms: authentication, authorization, role‑based access control (RBAC). Example: A SCADA workstation requires a user to log in with a password before any engineering functions are available. Challenge: Balancing strict controls with the need for rapid response in emergency situations.
Advanced Persistent Threat (APT) – a prolonged, targeted cyber‑attack whe… #
Related terms: zero‑day exploit, command‑and‑control (C2), threat actor. Example: An APT group infiltrates an oil‑and‑gas control network to exfiltrate production data over months. Challenge: Detecting low‑and‑slow activity that blends with normal OT traffic.
Authentication – process of verifying the identity of a user, device, or… #
Related terms: multi‑factor authentication (MFA), password policy, digital certificate. Example: An operator uses a smart card plus PIN to access a PLC programming interface. Challenge: Implementing MFA without impeding time‑critical operations.
Authorization – granting or denying access rights to resources after auth… #
Related terms: access control list (ACL), privilege escalation, least privilege. Example: A maintenance engineer receives read‑only rights to sensor data but cannot modify control logic. Challenge: Maintaining accurate permission matrices as staff roles evolve.
Availability – ensuring that OT services and data are accessible when nee… #
Related terms: redundancy, disaster recovery, service‑level agreement (SLA). Example: A redundant PLC pair provides seamless failover if the primary controller fails. Challenge: Protecting availability while defending against denial‑of‑service attacks.
Baseline Configuration – a documented, approved set of system settings us… #
Related terms: hardening, configuration drift, audit. Example: A firewall rule set that permits only required protocols between engineering workstations and RTUs. Challenge: Keeping the baseline current amid frequent firmware updates.
Biometric Authentication – use of physiological traits such as fingerprin… #
Related terms: multifactor authentication, spoofing, liveness detection. Example: A control room door unlocks only after a fingerprint scan matches an authorized operator. Challenge: Ensuring reliability in harsh industrial environments.
Black‑Box Testing – security testing where the tester has no prior knowle… #
Related terms: penetration testing, vulnerability scanning, red teaming. Example: A pen‑tester attempts to breach a PLC network without architecture diagrams. Challenge: Limited visibility may miss subtle configuration weaknesses.
Botnet – a network of compromised devices controlled remotely to perform… #
Related terms: command‑and‑control (C2), malware, distributed denial‑of‑service (DDoS). Example: Infected HMIs are enlisted to flood a utility’s public portal, disrupting customer access. Challenge: Detecting compromised OT assets that exhibit normal operational behavior.
Bridge (Network) – a device that connects two LAN segments, forwarding tr… #
Related terms: switch, router, segmentation. Example: A Ethernet bridge links a legacy serial network to a modern IP subnet without altering protocols. Challenge: Ensuring the bridge does not become a conduit for lateral movement.
Certificate Authority (CA) – trusted entity that issues digital certifica… #
Related terms: PKI, TLS/SSL, revocation list. Example: A SCADA server presents a certificate signed by the plant’s internal CA to prove its identity to remote HMI clients. Challenge: Managing certificate lifecycles across heterogeneous OT devices.
Change Management – formal process for requesting, reviewing, approving,… #
Related terms: configuration control, versioning, risk assessment. Example: Before upgrading a PLC firmware, a change request is logged, reviewed by the safety team, and scheduled during a maintenance window. Challenge: Balancing the need for rapid patches with rigorous approval procedures.
Chroot Jail – a security mechanism that isolates a process to a specific… #
Related terms: containerization, sandbox, least privilege. Example: A legacy data logger runs inside a chroot jail to limit its access to the file system. Challenge: Ensuring the jail does not inadvertently expose privileged binaries.
Cipher Suite – a set of algorithms that provide encryption, integrity, an… #
Related terms: TLS, SSL, cryptographic protocol. Example: A DNP3 Secure Authentication implementation selects AES‑256‑GCM as its cipher suite. Challenge: Selecting suites compatible with constrained OT devices while maintaining strong security.
Compliance – adherence to legal, regulatory, or industry standards govern… #
Related terms: ISO 27001, NIS Directive, GDPR. Example: A UK water utility must demonstrate compliance with the NIS 2 regulations concerning critical infrastructure. Challenge: Mapping technical controls to high‑level regulatory language.
Compromise Assessment – systematic evaluation to determine if an OT envir… #
Related terms: incident response, forensics, indicator of compromise (IOC). Example: After a ransomware alert, the security team conducts a compromise assessment on the control network to locate malicious binaries. Challenge: Performing deep analysis without disrupting real‑time processes.
Confidentiality – ensuring that information is disclosed only to authoriz… #
Related terms: encryption, access control, data classification. Example: Proprietary process parameters are encrypted at rest on the historian server. Challenge: Protecting data while maintaining low latency for control loops.
Control System Cybersecurity (CSCY) – discipline focused on protecting in… #
Related terms: OT security, ICS hardening, risk management. Example: A CSCY program implements network segmentation, intrusion detection, and patch management for a petrochemical plant. Challenge: Integrating CSCY practices with existing safety and operational standards.
Credential Dumping – extraction of password hashes or tokens from memory… #
Related terms: LSASS, privilege escalation, password cracking. Example: An attacker uses a tool to dump Windows administrator hashes from a supervisory workstation. Challenge: Detecting dumping activity on systems that rarely produce logs.
Cross‑Site Scripting (XSS) – web vulnerability where malicious scripts ar… #
Related terms: web application firewall (WAF), input validation, client‑side attack. Example: A HMI web portal fails to sanitize user input, allowing an attacker to execute JavaScript in the browser of another operator. Challenge: Many OT HMIs are built on legacy web stacks with limited patching.
Cyber‑Physical System (CPS) – integration of computation, networking, and… #
Related terms: IoT, OT, digital twin. Example: A smart grid uses sensors, controllers, and communication links to balance supply and demand in real time. Challenge: Securing the cyber layer without compromising the timing constraints of the physical layer.
Data Diodes – hardware devices that enforce unidirectional data flow, pre… #
Related terms: air gap, one‑way gateway, network segmentation. Example: A historian receives telemetry from field devices through a data diode, ensuring that no commands can travel back. Challenge: Configuring monitoring and management channels that still respect the one‑way restriction.
Defense‑in‑Depth – layered security approach that combines multiple contr… #
Related terms: perimeter security, host hardening, application security. Example: A refinery employs firewalls, intrusion detection systems, host hardening, and user training to defend its control network. Challenge: Avoiding unnecessary complexity that can obscure visibility.
Deception Technology – use of decoys, honeypots, and fake assets to lure… #
Related terms: honeynet, threat hunting, indicator of attack (IOA). Example: A simulated PLC with fake registers is deployed in a DMZ to detect lateral movement attempts. Challenge: Ensuring decoys do not interfere with legitimate traffic or safety functions.
Denial‑of‑Service (DoS) – attack that exhausts resources, rendering a sys… #
Related terms: DDoS, bandwidth saturation, service disruption. Example: An attacker floods a SCADA server with malformed packets, causing the control interface to freeze. Challenge: Distinguishing malicious traffic from legitimate bursts caused by process spikes.
Digital Twin – virtual replica of a physical asset used for simulation, m… #
Related terms: CPS, model‑based engineering, predictive maintenance. Example: A digital twin of a turbine is synchronized with real‑time sensor data to predict failures. Challenge: Securing the twin’s data feed to prevent manipulation of the physical system.
Disaster Recovery (DR) – strategy for restoring IT/OT services after a ca… #
Related terms: business continuity, backup, RPO/RTO. Example: A backup of the control system configuration is stored off‑site and can be restored within four hours after a fire. Challenge: Testing DR plans without interrupting production.
DMZ (Demilitarized Zone) – network segment that isolates external‑facing… #
Related terms: perimeter firewall, segmentation, jump host. Example: A Historian web interface resides in a DMZ, allowing remote engineers to view trends without direct access to the control network. Challenge: Configuring strict rules to prevent DMZ compromise from propagating inward.
DNS Spoofing – attack that corrupts DNS responses to redirect traffic to… #
Related terms: cache poisoning, man‑in‑the‑middle (MITM), secure DNS (DNSSEC). Example: An attacker modifies the DNS entry for a firmware update server, causing devices to download a trojanized image. Challenge: Many OT devices rely on static DNS entries that are difficult to update.
Domain‑Based Security – approach that groups assets by logical or functio… #
Related terms: security zones, risk segmentation, policy enforcement. Example: A “process control” domain has stricter authentication than a “monitoring” domain. Challenge: Maintaining clear boundaries as systems interconnect for Industry 4.0 Initiatives.
Edge Computing – processing data close to the source rather than in a cen… #
Related terms: fog computing, latency, distributed architecture. Example: A PLC performs local analytics on vibration data to trigger an alarm before sending summary data to the cloud. Challenge: Ensuring edge nodes are patched and monitored despite limited management interfaces.
Endpoint Detection and Response (EDR) – tools that monitor, detect, and r… #
Related terms: host‑based IDS, forensics, behavioral analytics. Example: An EDR agent on an engineering workstation records process creation events to flag suspicious script execution. Challenge: Deploying agents on legacy OT equipment with constrained resources.
Encryption – transformation of data into unreadable form using algorithms… #
Related terms: cipher, key management, TLS. Example: TLS is used to secure MQTT messages sent from field sensors to a central broker. Challenge: Selecting encryption that meets performance constraints of real‑time control loops.
Enterprise Risk Management (ERM) – systematic process for identifying, as… #
Related terms: risk register, ISO 31000, risk appetite. Example: A utility incorporates OT cyber‑risk assessments into its overall ERM framework to align with corporate governance. Challenge: Translating technical vulnerabilities into business‑level risk metrics.
Exfiltration – unauthorized transfer of data from a target system to an e… #
Related terms: data leakage, command‑and‑control (C2), staging. Example: Malware compresses PLC program files and uploads them to a remote server via an outbound HTTPS connection. Challenge: Monitoring outbound traffic in environments where external communication is limited but essential.
Fail‑Safe – design principle where a system defaults to a safe state in t… #
Related terms: fail‑secure, redundancy, safe‑state. Example: If a valve controller loses power, it automatically closes to prevent over‑pressure. Challenge: Ensuring security controls (e.G., Authentication) do not inadvertently prevent safe‑state activation.
Firewall – network security device that filters traffic based on predefin… #
Related terms: stateful inspection, packet filtering, network segmentation. Example: A next‑generation firewall blocks all inbound traffic to the control network except for specific SCADA protocols from authorized management stations. Challenge: Correctly mapping industrial protocol ports to avoid accidental blockage of critical traffic.
Forward Secrecy – cryptographic property that ensures session keys cannot… #
Related terms: Diffie‑Hellman, key exchange, TLS. Example: A TLS configuration that uses ECDHE provides forward secrecy for encrypted telemetry streams. Challenge: Some legacy OT devices only support static RSA key exchange, lacking forward secrecy.
Fuzz Testing – automated technique that supplies random or malformed inpu… #
Related terms: software testing, buffer overflow, security assessment. Example: A fuzzer targets the Modbus TCP stack of a PLC to uncover parsing errors. Challenge: Ensuring that fuzzing does not disrupt live processes or safety functions.
Hardened Operating System – OS configuration that removes unnecessary ser… #
Related terms: minimal install, security baseline, system hardening. Example: A PLC runs a hardened Linux kernel with only the Modbus daemon enabled. Challenge: Maintaining hardening while supporting vendor‑specific drivers required for field I/O.
Incident Response (IR) – coordinated approach to detect, contain, eradica… #
Related terms: playbook, forensics, post‑mortem. Example: An IR team follows a predefined playbook to isolate a compromised engineering workstation, collect volatile memory, and restore from a known‑good image. Challenge: Executing IR steps without halting critical production processes.
Industrial Control System (ICS) – integrated hardware and software that m… #
Related terms: SCADA, PLC, DCS. Example: A water treatment plant uses a DCS to manage pump sequencing, valve positions, and chemical dosing. Challenge: Protecting legacy components that were not designed with security in mind.
Industrial Internet of Things (IIoT) – networked sensors, actuators, and… #
Related terms: edge computing, cloud integration, digital transformation. Example: Smart meters transmit consumption data over MQTT to a utility’s analytics platform. Challenge: Integrating heterogeneous devices while maintaining a consistent security posture.
Intrusion Detection System (IDS) – technology that monitors network or ho… #
Related terms: signature‑based, anomaly‑based, alerting. Example: A network IDS flags an unexpected Modbus “Write Multiple Registers” command originating from a workstation that normally only reads data. Challenge: Tuning IDS thresholds to reduce false positives that could lead to alarm fatigue.
IP Whitelisting – security method that permits traffic only from explicit… #
Related terms: access control list (ACL), network segmentation, firewall rule. Example: Only the IP of the central historian is allowed to connect to the PLC’s configuration port. Challenge: Managing dynamic IP allocations in environments with DHCP or mobile devices.
Key Management – processes and tools for generating, storing, rotating, a… #
Related terms: PKI, HSM, certificate lifecycle. Example: An HSM stores AES keys used to encrypt archived process data, with automatic rotation every 90 days. Challenge: Integrating key management with devices that lack native support for secure storage.
Kill Chain – model describing the stages of a cyber attack from reconnais… #
Related terms: MITRE ATT&CK, threat hunting, defense‑in‑depth. Example: An attacker follows the kill chain by first scanning for open ports, then exploiting a PLC firmware vulnerability, and finally exfiltrating data. Challenge: Breaking the chain early requires proactive detection at each stage.
Least Privilege – principle that users and processes receive only the acc… #
Related terms: role‑based access control (RBAC), privilege escalation, access review. Example: A contractor’s account can view sensor trends but cannot modify control parameters. Challenge: Regularly reviewing privileges as job responsibilities evolve.
Logical Segmentation – division of a network into separate zones using vi… #
Related terms: DMZ, firewall, micro‑segmentation. Example: The engineering workstations reside in VLAN 10, while field devices are placed in VLAN 20, with strict inter‑VLAN ACLs. Challenge: Ensuring segmentation does not interfere with time‑sensitive control traffic.
Malware – malicious software designed to disrupt, damage, or gain unautho… #
Related terms: ransomware, trojan, rootkit. Example: A ransomware variant encrypts PLC configuration files, demanding payment to restore operation. Challenge: Limited visibility into proprietary file systems that may hide malware artifacts.
Man‑in‑the‑Middle (MITM) – attack where the adversary intercepts and poss… #
Related terms: packet injection, SSL stripping, session hijacking. Example: An attacker positions a rogue device on the control network to modify Modbus commands before they reach a valve controller. Challenge: Detecting subtle timing changes or packet modifications in high‑throughput environments.
Man‑In‑The‑Browser (MITB) – attack that injects malicious code into a web… #
Related terms: web shell, phishing, browser hijack. Example: An operator’s HMI web client is compromised, allowing the attacker to change set‑points displayed on the screen. Challenge: Many industrial browsers lack modern security extensions.
Micro‑Segmentation – granular network segmentation that isolates workload… #
Related terms: software‑defined perimeter, zero‑trust, policy enforcement point. Example: Each PLC is assigned a unique security policy that only permits communication from its designated supervisory system. Challenge: Creating and maintaining hundreds of policies without overwhelming administrators.
MITRE ATT&CK® for OT – knowledge base of adversary tactics and techniques… #
Related terms: kill chain, threat modeling, security controls. Example: The “Manipulation of PLC Logic” technique is mapped to detection controls such as configuration integrity monitoring. Challenge: Aligning ATT&CK mappings with existing security tooling that may be IT‑centric.
Network Time Protocol (NTP) – protocol for synchronizing clocks of comput… #
Related terms: time drift, chrony, security. Example: PLCs use NTP to timestamp events, enabling accurate forensic analysis after an incident. Challenge: NTP can be abused for amplification attacks if not properly secured.
Network Topology – physical and logical arrangement of network nodes and… #
Related terms: bus, star, ring. Example: A ring topology provides redundancy for critical communication between master and slave devices. Challenge: Documenting topology accurately to support impact analysis during change management.
Non‑Repudiation – assurance that a party cannot deny the authenticity of… #
Related terms: digital signature, audit log, integrity. Example: A signed command to open a valve provides evidence that the authorized operator initiated the action. Challenge: Storing signatures in tamper‑proof logs while respecting limited storage on embedded devices.
Obfuscation – technique that makes code or data harder to analyze, often… #
Related terms: packer, encryption, anti‑analysis. Example: A malicious DLL uses code obfuscation to hide its payload from static analysis tools. Challenge: Distinguishing legitimate code obfuscation (e.G., For intellectual property protection) from malicious intent.
Off‑The‑Shelf (OTS) Software – commercially available software not specif… #
Related terms: COTS, vendor support, compatibility. Example: A generic Windows workstation runs a third‑party HMI client. Challenge: Ensuring OTS software receives timely security updates while maintaining operational continuity.
One‑Way Authentication – process where only one party verifies the identi… #
Related terms: server authentication, mutual TLS, certificate validation. Example: An HMI validates the server certificate of a PLC, but the PLC does not verify the HMI’s identity. Challenge: Unilateral trust can be exploited if the client is compromised.
Open‑Source Software (OSS) – software whose source code is publicly avail… #
Related terms: community support, vulnerability disclosure, license compliance. Example: An open‑source MQTT broker is used to aggregate sensor data. Challenge: Tracking OSS dependencies to ensure patches are applied promptly.
Operational Technology (OT) – hardware and software that monitors and con… #
Related terms: ICS, SCADA, process automation. Example: A series of PLCs managing a gas compression station constitute the OT layer. Challenge: Integrating OT security with existing IT governance frameworks.
Patch Management – systematic process for acquiring, testing, and deployi… #
Related terms: vulnerability remediation, change control, rollback. Example: A monthly maintenance window is used to apply vendor‑released firmware patches to all field devices. Challenge: Balancing the need for rapid patching against the risk of introducing instability into live control loops.
Phishing – social engineering technique that attempts to trick recipients… #
Related terms: spear phishing, credential harvesting, email spoofing. Example: An engineer receives an email appearing to be from the vendor, containing a link to a malicious DLL. Challenge: Training OT staff to recognize sophisticated, industry‑specific phishing attempts.
Physical Security – measures that protect equipment and facilities from u… #
Related terms: access control, surveillance, tamper‑evident seals. Example: A locked cabinet houses the primary network switch for the control zone. Challenge: Coordinating physical and logical security to avoid gaps where an attacker could bypass network controls.
PLC (Programmable Logic Controller) – industrial computer that executes c… #
Related terms: ladder logic, firmware, IO modules. Example: A PLC reads sensor inputs, runs a control algorithm, and drives actuator outputs for a conveyor system. Challenge: Securing the PLC against unauthorized code changes while preserving deterministic execution.
Port Scanning – technique used to discover open network ports on a target… #
Related terms: network reconnaissance, Nmap, service enumeration. Example: A security analyst runs a scan to identify which Modbus ports are exposed on the field network. Challenge: Scanning can disrupt time‑critical traffic if not performed carefully.
Privileged Access Management (PAM) – controls that secure, monitor, and a… #
Related terms: password vault, session recording, just‑in‑time access. Example: An admin uses a PAM solution to retrieve a one‑time password for a PLC before applying a firmware update. Challenge: Integrating PAM with legacy devices that lack API support.
Protocol Anomaly Detection – monitoring technique that flags deviations f… #
Related terms: behavioral analytics, IDS, baseline profiling. Example: A DNP3 master sends a “Write” command to a slave that normally only receives “Read” requests, triggering an alert. Challenge: Defining normal protocol patterns in environments with mixed vendor implementations.
Public Key Infrastructure (PKI) – framework for managing digital certific… #
Related terms: certificate authority (CA), CRL, TLS. Example: Each HMI receives a client certificate from the plant PKI to authenticate to the historian. Challenge: Provisioning and renewing certificates on devices with limited UI.
Q‑Rating (IEC 61850) – security rating that assesses the resilience of co… #
Related terms: IEC 62443, security level (SL), risk assessment. Example: A substation relay is evaluated to meet a Q‑Rating of 4, indicating strong resistance to network‑based threats. Challenge: Achieving high Q‑Ratings while maintaining compatibility with legacy field equipment.
Ransomware – malicious software that encrypts data and demands payment fo… #
Related terms: crypto‑locker, extortion, backup strategy. Example: A ransomware variant encrypts the configuration files of a DCS, preventing operators from changing set‑points. Challenge: Restoring from backups without violating safety integrity during the recovery window.
Remote Access VPN – secure tunnel that enables authorized users to connec… #
Related terms: two‑factor authentication, split tunneling, network segmentation. Example: An off‑site engineer uses a VPN to access the plant’s engineering workstation for a scheduled update. Challenge: Ensuring VPN traffic is inspected and does not bypass segmentation controls.
Replay Attack – attempt to resend captured network packets to repeat a pr… #
Related terms: nonce, timestamp, integrity check. Example: An attacker replays a valid “open valve” command captured earlier, causing unintended operation. Challenge: Implementing anti‑replay mechanisms in protocols that lack built‑in sequence numbers.
Risk Assessment – process of identifying, evaluating, and prioritizing ri… #
Related terms: threat modeling, impact analysis, risk matrix. Example: A risk assessment identifies the loss of confidentiality of process parameters as a moderate risk, prompting encryption at rest. Challenge: Quantifying impact on safety and production continuity.
Safety‑Integrated Security (SIS) – approach that aligns safety and securi… #
Related terms: IEC 61508, IEC 62443, risk reduction. Example: A safety‑instrumented system (SIS) includes authentication checks before allowing a manual override. Challenge: Avoiding conflicts where security measures unintentionally inhibit safety functions.
Secure Boot – hardware‑based process that verifies the integrity of firmw… #
Related terms: trusted platform module (TPM), code signing, root of trust. Example: A PLC’s bootloader checks a digital signature on the firmware image, refusing to load tampered code. Challenge: Managing keys across a large fleet of devices with limited management interfaces.
Security Information and Event Management (SIEM) – platform that aggregat… #
Related terms: log collection, correlation rules, alerting. Example: A SIEM correlates a failed login on a workstation with a simultaneous outbound connection to a known C2 server. Challenge: Normalizing logs from proprietary OT protocols that lack standard syslog output.
Security Operations Center (SOC) – centralized team responsible for monit… #
Related terms: threat hunting, incident response, playbooks. Example: The SOC receives an alert from an IDS about anomalous Modbus traffic and initiates a containment workflow. Challenge: Staffing the SOC with expertise in both IT and OT domains.
Security Level (SL) – defined set of security requirements from IEC 62443… #
Related terms: risk assessment, defense‑in‑depth, Q‑Rating. Example: A critical substation is required to meet SL‑3, mandating strong authentication and encryption for all external connections. Challenge: Achieving higher SLs without impairing real‑time control performance.
Secure Firmware Update – process that ensures firmware is authentic, inte… #
Related terms: code signing, rollback protection, OTA (over‑the‑air). Example: A PLC receives a signed firmware image via a secure OTA channel, verifies the signature, and writes it to a protected partition. Challenge: Handling devices that lack built‑in secure update mechanisms.
Segmentation – practice of dividing a network into zones to limit the spr… #
Related terms: DMZ, VLAN, firewall. Example: The control network is segmented from the corporate IT network by a firewall that permits only specific management protocols. Challenge: Maintaining necessary communication paths for engineering while preventing unauthorized lateral movement.
Secure Shell (SSH) – cryptographic network protocol for secure remote log… #
Related terms: public key authentication, port forwarding, hardening. Example: An engineer uses SSH with key‑based authentication to access a PLC’s console for troubleshooting. Challenge: Ensuring SSH is disabled on devices where it is not required to reduce attack surface.
Supply Chain Attack – compromise of hardware or software components durin… #
Related terms: software trojan, hardware backdoor, trusted supplier. Example: A compromised firmware image is inserted into a PLC during a vendor’s third‑party assembly process. Challenge: Verifying provenance of components in a global supply network.
Threat Intelligence – information about adversaries, tactics, techniques,… #
Related terms: IOC, CTI, feed. Example: A feed provides hashes of known OT‑targeted malware, which are used to update detection signatures. Challenge: Correlating generic threat intel with the specific asset inventory of an OT environment.
Threat Modeling – systematic analysis of potential threats to determine w… #
Related terms: attack trees, STRIDE, risk assessment. Example: A threat model identifies “unauthorized PLC reprogramming” as a high‑impact scenario, leading to the implementation of code signing. Challenge: Capturing complex interactions between physical processes and cyber assets.
Time‑Based One‑Time Password (TOTP) – algorithm that generates a short‑li… #
Related terms: MFA, Google Authenticator, HOTP. Example: A field engineer uses a TOTP token on a mobile device to authenticate to a remote HMI. Challenge: Ensuring device clocks remain synchronized to avoid login failures.
Transport Layer Security (TLS) – cryptographic protocol that provides pri… #
Related terms: handshake, cipher suite, certificate. Example: An MQTT broker enforces TLS 1.2 For all client connections, encrypting telemetry data in transit.