EN 50742 in 5 Minutes: The First EU Standard to Merge Machinery Safety and Cybersecurity

Introduction

Imagine your company’s industrial machinery operating smoothly in a European factory when suddenly unauthorized code execution causes the safety system to fail, leading to dangerous situations. This is not hypothetical—it’s a real risk that pr EN 50742 aims to prevent.

pr EN 50742 (Safety of machinery - Protection against corruption) is the EU’s first harmonized standard that comprehensively integrates mechanical safety with cybersecurity. It addresses the critical need to prevent intentional or unintentional corruption of machinery control systems that could lead to hazardous situations.

30-Second Core Takeaway: pr EN 50742 introduces the SRSL (Safety-Related Security Level) system, offering dual compliance pathways (Method A and Method B) to protect machinery control systems from corruption. It will become a harmonized standard under the new Machinery Directive (EU) 2023/1230, making it essential for machinery manufacturers targeting the EU market.

What is pr EN 50742?

Standard Positioning

pr EN 50742 is the European standard for “Safety of machinery - Protection against corruption”.

Basic Information	Content
Standard Number	pr EN 50742
English Title	Safety of machinery - Protection against corruption
Document Type	European Standard Draft (DRAFT)
Publication Date	December 2025
Enquiry Deadline	February 27, 2026
Developing Organization	CENELEC CLC/TC 44X
Pages	67 pages

Relationship with Machinery Directive

This standard is designed to be a harmonized standard under the new Machinery Directive (EU) 2023/1230. Compliance with harmonized standards provides presumption of conformity with the essential requirements specified in the Directive.

Key Articles Addressed:

• Annex III, Article 1.1.9: Protection against corruption
• Annex III, Article 1.2.1: Control system safety and reliability

Why a New Standard?

Traditional machinery safety standards focused primarily on functional safety (preventing failures). pr EN 50742 addresses the emerging threat landscape where:

• Connected machinery introduces new attack surfaces
• Software updates can be corrupted maliciously
• Remote access creates unauthorized intervention risks
• Supply chain attacks can compromise safety-critical components

The standard fills the gap between traditional functional safety and modern cybersecurity threats.

Core Innovation: The Corruption Concept

What is “Corruption”?

Corruption is the central concept of pr EN 50742, defined as:

“Accidental or illegal modification of machinery data that could lead to a hazardous situation.”

This differs from traditional safety concepts:

Concept	Traditional Safety	pr EN 50742
Focus	Random failures and errors	Intentional malicious acts
Threat Model	Environmental factors, wear	Cyberattacks, unauthorized modifications
Prevention	Redundancy, diagnostics	Authentication, encryption, integrity verification

Key Characteristics of Corruption

┌─────────────────────────────────────────────────────────────────┐
│                    Corruption Characteristics                  │
├─────────────────────────────────────────────────────────────────┤
│                                                                 │
│  1. Data Integrity Compromised                                  │
│     - Software code modifications                               │
│     - Configuration parameter changes                           │
│     - Safety-critical data corruption                           │
│                                                                 │
│  2. Can Affect Safety Functions                                 │
│     - Bypassing safety interlocks                               │
│     - Altering speed/position limits                            │
│     - Disabling emergency stops                                 │
│                                                                 │
│  3. Caused by Accidental or Malicious Acts                      │
│     - Accidental: Configuration errors, unauthorized updates    │
│     - Malicious: Cyberattacks, insider threats                  │
│                                                                 │
└─────────────────────────────────────────────────────────────────┘

Three Major Innovations

pr EN 50742 introduces three groundbreaking innovations that distinguish it from traditional safety standards:

Innovation 1: SRSL System

SRSL (Safety-Related Security Level) is a four-tier security classification system:

SRSL Level	Description	Typical Threat Scenario
SRSL0	Complete isolation, no special requirements	Fully isolated network, no external interfaces
SRSL1	Low attack potential	Attacks only possible under very specific conditions, reversible harm
SRSL2	Medium attack potential	Attacks have reasonable likelihood, reversible harm
SRSL3	High attack potential	High likelihood or virtually guaranteed, irreversible harm

SRSL Determination Process:

1. Complete Threat Assessment (STRIDE methodology)
   ↓
2. Calculate Attack Potential (AP)
   AP = (Exposure Level × Window of Opportunity) + Attacker Capability
   ↓
3. Determine Injury Severity
   - Low: Reversible injury
   - High: Irreversible injury or death
   ↓
4. Look up SRSL Level from standard table

Innovation 2: Dual Compliance Pathways

pr EN 50742 offers two equivalent compliance pathways—manufacturers must choose one:

┌─────────────────────────────────────────────────────────────────┐
│                 pr EN 50742 Dual Compliance Architecture        │
├─────────────────────────────────────────────────────────────────┤
│                                                                 │
│              Common Foundation Requirements (Mandatory)         │
│         ┌────────────────────────────────────────┐             │
│         │  • EN ISO 12100 Risk Assessment         │             │
│         │  • Clause 4 - Corruption Protection     │             │
│         │  • Clause 9 - Use Information           │             │
│         └────────────────────────────────────────┘             │
│                              │                                  │
│              ┌───────────────┴───────────────┐                 │
│              │                               │                 │
│              ▼                               ▼                 │
│  ┌───────────────────┐           ┌───────────────────┐        │
│  │    Method A       │           │    Method B       │        │
│  │  (Clauses 5, 7)   │           │ (Clauses 6, 8)   │        │
│  ├───────────────────┤           ├───────────────────┤        │
│  │ • Self-contained  │           │ • References      │        │
│  │   requirements    │           │   IEC 62443 series│        │
│  │ • SRSL system     │           │ • SL security     │        │
│  │   (0-3)           │           │   levels          │        │
│  │ • Independent     │           │ • Integrated with │        │
│  │   & complete      │           │   existing 62443  │        │
│  └───────────────────┘           └───────────────────┘        │
│                                                                 │
└─────────────────────────────────────────────────────────────────┘

Method A vs Method B Comparison:

Aspect	Method A (Self-contained)	Method B (References IEC 62443)
Complexity	Lower, standalone requirements	Higher, requires 62443 framework understanding
Target Audience	Manufacturers without cybersecurity experience	Manufacturers with existing cybersecurity frameworks
Certification Timeline	Shorter (2-3 months)	Longer (3-4 months)
Documentation Effort	~20-38 person-days	~30-50 person-days
Market Recognition	EU machinery sector	Global industrial automation sector

Innovation 3: Integrated Threat Assessment

pr EN 50742 integrates threat assessment directly with the traditional EN ISO 12100 risk assessment methodology:

Traditional Risk Assessment (EN ISO 12100)
    ↓
+ Enhanced with Cybersecurity Threats
    ↓
Integrated Risk & Threat Assessment
    ↓
Comprehensive Protection Against Both Safety and Security Hazards

Key Integration Points:

1. Hazard Identification: Includes both traditional safety hazards and cybersecurity threats
2. Risk Estimation: Combines severity, probability, and attack potential
3. Risk Reduction: Applies both safety measures and security countermeasures
4. Verification: Validates both functional safety and cybersecurity effectiveness

Who Needs to Comply?

Scope of Application

pr EN 50742 applies to:

Target Group	Applicability
Machinery Manufacturers	Primary applicability - all machinery types
Component Suppliers	Safety-related control system components
System Integrators	Integrated machinery systems
Machinery Users	For modifications and major retrofits

Applicable Products

The standard covers:

Product Category	Examples
Safety-Related Control Systems (SRP/CS)	Safety PLCs, safety relays, light curtains
Programmable Safety Systems	Safety controllers, safety HMI
Safety-Related Embedded Software (SRESW)	System software provided by manufacturer
Safety-Related Application Software (SRASW)	Application logic and control sequences
Network Interfaces	All interfaces that can affect safety functions

When Does It Apply?

Scenario	Requirement
New Machinery	Mandatory compliance
Substantial Modifications	Must comply with updated requirements
Existing Machinery	Not retroactive, but major modifications require compliance
Components Placed on Market	Must comply if used in safety-related systems

Key Technical Requirements

Interface Protection (Clause 7.1)

All accessible interfaces that can affect machinery safety must be:

1. Identified: Complete interface inventory
2. Protected: Using countermeasures or compensating countermeasures

Interface Types and Protection:

Interface Type	Examples	Protection Measures
Physical Interfaces	USB, RJ45, SD cards	Physical seals, disable, authentication
Wireless Interfaces	WiFi, Bluetooth	Encryption, authentication, disable
Network Interfaces	Ethernet, fieldbus	Network segmentation, firewalls, encryption
Remote Interfaces	VPN, cloud services	Strong authentication, encryption, audit

Integrity Verification (Clause 7.2)

Requirements by SRSL level:

SRSL Level	Integrity Verification Requirements
SRSL0	No special requirements
SRSL1	Boot-time checksum verification
SRSL2	Boot-time + periodic checksum verification
SRSL3	Encrypted verification (HMAC/CMAC) + periodic verification

Logging and Evidence (Clause 7.3)

Required Logging Categories:

1. Safety parameterization/configuration changes
2. SRESW (embedded software) updates/modifications
3. SRASW (application software) updates/modifications
4. HMI parameterization (if potentially hazardous)
5. Software displaying safety instructions

Minimum Data Elements:

Data Element	Description
Intervention Type	Type of intervention affecting safety-related software
Timestamp	Precise time of intervention
Operator	Entity performing the intervention (user/system)
Asset	Identifier of the affected asset
Change Content	Values before and after the change

Storage Requirements:

• Enable from machinery commissioning
• Retention period: At least 5 years
• Quantity: At least the last intervention of each type
• Protection: Tamper-resistant, deletion requires authorization

Relationship with Functional Safety

Complementary, Not Replacement

pr EN 50742 does not replace functional safety requirements (such as EN ISO 13849 or IEC 62061). Instead, it complements them:

┌─────────────────────────────────────────────────────────────────┐
│              Functional Safety + Cybersecurity Integration      │
├─────────────────────────────────────────────────────────────────┤
│                                                                 │
│  Functional Safety (EN ISO 13849, IEC 62061)                   │
│  • Prevents random failures and systematic errors              │
│  • Focuses on reliability and deterministic behavior           │
│                                                                 │
│                         +                                       │
│                                                                 │
│  Cybersecurity (pr EN 50742)                                   │
│  • Prevents intentional corruption and unauthorized access      │
│  • Focuses on integrity and authentication                     │
│                                                                 │
│                         =                                       │
│                                                                 │
│  Comprehensive Machinery Safety Protection                     │
│  • Addresses both accidental and intentional hazards           │
│  • Covers entire threat spectrum                                │
│                                                                 │
└─────────────────────────────────────────────────────────────────┘

Safety-Related Software Classification

The standard distinguishes between:

Software Type	Definition	Example
SRESW	Safety-Related Embedded Software	System firmware, operating system
SRASW	Safety-Related Application Software	Control logic, safety functions

Both types require protection against corruption, but with different approaches based on the SRSL level.

Why Certification Matters

Regulatory Compliance

1. Legal Requirement: Once published as a harmonized standard, compliance is mandatory for CE marking
2. Market Access: Certification is essential for EU market entry
3. Presumption of Conformity: Certified products automatically meet Machinery Directive requirements

Business Benefits

Benefit	Description
Competitive Advantage	Certification demonstrates commitment to machinery safety and cybersecurity
Risk Management	Systematic approach reduces cybersecurity incident risk
Customer Trust	Certification mark enhances product credibility
Insurance Benefits	May reduce cybersecurity insurance premiums

Certification Timeline

Phase	Duration	Description
Preparation	2-4 weeks	Standard understanding, team building, pathway selection
Pre-assessment	1-2 weeks	Questionnaire, scope determination, preliminary results
Threat Assessment & SRSL	4-8 weeks	Risk assessment, threat modeling, level determination
Implementation	8-16 weeks	Security measures implementation, documentation
Document Review	2-4 weeks	Certification body document review
On-site Audit	1-2 weeks	On-site inspection, testing, interviews
Certification Decision	2-4 weeks	Technical review, decision, certificate issuance
Total	4-9 months	Depends on SRSL level and preparation

Getting Started

Immediate Action Items

If you’re a machinery manufacturer targeting the EU market, here’s what you should do:

1. Assess Your Products

   • Identify which products fall within scope
   • Determine network connectivity and exposure level
   • Assess current cybersecurity measures

2. Choose Your Compliance Pathway

   • Evaluate Method A vs Method B suitability
   • Consider existing cybersecurity investments
   • Assess internal capabilities

3. Build Your Team

   • Assign a project manager
   • Identify safety and security engineers
   • Engage with certification body early

4. Conduct Gap Analysis

   • Compare current practices against pr EN 50742 requirements
   • Identify necessary improvements
   • Develop implementation roadmap

5. Begin Documentation Preparation

   • System architecture documentation
   • Threat assessment methodology
   • Security measures inventory

Common Mistakes to Avoid

Mistake	Consequence	Best Practice
Waiting until standard is published	Rushed implementation, higher costs	Start preparation now using draft standard
Treating it as purely IT issue	Inadequate safety integration	Involve both safety and security teams
Underestimating documentation	Audit delays, non-conformities	Start documentation early
Choosing wrong pathway	Wasted time and resources	Assess organizational context carefully
Ignoring existing processes	Duplicate work, inefficiency	Integrate with existing safety processes

Key Takeaways

Let’s summarize pr EN 50742 with 5 core points:

1. First Integrated Standard pr EN 50742 is the EU’s first standard to comprehensively integrate machinery safety and cybersecurity, addressing the corruption of safety-related control systems.

2. SRSL Innovation The four-tier SRSL system provides a clear framework for determining appropriate security levels based on attack potential and injury severity.

3. Dual Compliance Pathways Method A (self-contained) and Method B (referencing IEC 62443) offer equivalent compliance effectiveness, allowing manufacturers to choose based on their organizational context.

4. Complementary to Functional Safety The standard complements, not replaces, functional safety requirements (EN ISO 13849, IEC 62061), creating comprehensive machinery protection.

5. Immediate Preparation Needed Although currently in draft stage, manufacturers should start preparation now. The certification process takes 4-9 months, and early adopters will have competitive advantage.

Further Reading

pr EN 50742 is a comprehensive standard, and this article is just an overview. For deeper understanding, explore:

• Method A vs Method B: Detailed comparison and selection criteria
• SRSL Level Guide: In-depth explanation of each security level
• Certification Preparation: Step-by-step implementation guidance
• Case Studies: Real-world examples from early adopters

Professional Tip: pr EN 50742 compliance requires collaboration between safety engineers, cybersecurity specialists, and certification experts. Start with a gap assessment against the draft standard and engage with your certification body early to understand specific requirements for your products.

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Reference Sources

• pr EN 50742:2025 - Safety of machinery - Protection against corruption
• Machinery Directive (EU) 2023/1230
• EN ISO 12100:2010 - Safety of machinery - General principles for design - Risk assessment and risk reduction
• EN IEC 62443-3-3:2019 - Security for industrial automation and control systems

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Article Information

• Article ID: art-021
• Slug: en-50742-overview
• Type: Concept Introduction
• Target Audience: Management, Product Managers, Safety Engineers
• Publication Date: 2026-03-14
• Estimated Reading Time: 5 minutes