Toralf Chryselius - PKI Software Developer and Trainer

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Hohen Neuendorf, Germany

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Experience

Jan 2025 - Nov 2025

11 months

IT Consultant in PKI Software Development

BWI

Implementation of a full-stack application with Angular as the frontend framework and Java as the backend language
Use of the Swagger OpenAPI specification for REST communication between the frontend and backend applications
Control of a card printer via the Nexus Card SDK framework
Design and implementation of card management software with a web interface and a JavaFX module for printer monitoring
Use of Cucumber tests for test automation and creation of test artifacts to test outside the development environment
Use of Wireshark for network investigations to analyze the API of a third-party product and to monitor the REST API of the self-developed software

Feb 2024 - Dec 2024

11 months

IT Consultant in PKI Software Development

BWI

Redevelopment of existing software using the Spring Boot 3 framework
Control of a Thales HSM from Java
Development of GUI tools with JavaFX 24
Use of Wireshark to monitor the REST API of the self-developed software

Feb 2023 - Aug 2023

7 months

Software Architect (Subject Matter Expert)

Techniker Krankenkasse

Formulation of requirements for Android and iOS development in Kotlin and Swift within a sprint
Improvement of the TK-Safe app with a focus on vaccine personalization
Creation of Scrum stories and acceptance criteria for bug fixes and new features

Jan 2022 - Dec 2022

1 year

Freelance Java Developer

BITMARCK

Development of software for describing health data for health insurance companies on JBOSS servers with J2EE
Use of the BDD language Gherkin in Cucumber for end-to-end tests with Selenium for the web interface in Java
Implementation of Clean Code principles and loose coupling between frameworks

Sep 2021 - Dec 2021

4 months

Freelance Java and Groovy Developer

Ingrano GmbH

Further development of existing tests for Worldline GmbH
Extension of the crypto library with features for generating RSA and ECC certificates in the X.509 domain
Revision of test design according to Clean Code paradigms

Apr 2021 - Aug 2021

5 months

Freelance Test Developer

Ingrano GmbH

Adaptation and new development of tests for the KoCo connector according to field test errors and TÜV IT specifications
Testing the cryptographic parameters of secure data transmission between the connector and the healthcare TI

Oct 2020 - Present

6 years

Developer and Training Lead

Velamentum

Development and redesign of the Velamentum ServerSuite as a full-stack project
Frontend: Angular 21 (TypeScript, CSS, HTML)
Backend: Go 1.25 with OpenAPI RESTful API
Development of a custom CA in Go to secure the RESTful interfaces and generate third-party certificates via SCEP
Use of Podman containers instead of Docker for rootless systemd support
Automated distribution of root certificates to various client operating systems and browsers
Integration and use of OpenVAS, Wazuh, Suricata, ClamAV, and Shuffle in self-designed containers
Creation of a training course with hardware (Raspberry Pi 5 or AMD64 machines) and training materials for practical network security

Sep 2019 - Mar 2021

1 year 7 months

Specification Engineer in the Patient Team

gematik GmbH

Further development of the specification for the architecture of the electronic patient record (ePA)
Overseeing the requirements lifecycle (AFOs) for ePA 1 through ePA 5
Implementing fine-grained access control according to the Patient Data Protection Act in the software architecture
Close coordination with spec authors of other components, ensuring technology neutrality and compatibility

Jan 2019 - Present

7 years 9 months

Lecturer in Computer Security, Penetration Testing, and IT System Hardening

Code University Berlin

Development and delivery of a block seminar in English
Setup of a Penetration Testing Lab (PenTestLab) as an open-source Java Spring Boot application to create and provision virtual machines with Vagrant and Ansible
Integration and management of Metasploit, ZenMap, Armitage, OpenVAS, Snort, OSSEC, and Graylog for practical training in attacks and monitoring

Jan 2017 - Aug 2019

2 years 8 months

Software Architect and Product Owner

T-Systems

Architecture and design of the T-Systems CA following Clean Code and SOLID principles for PKCS#12 containers and certificate packaging for terminal and card simulators
Role as Product Owner in a Scrum team (6–9 developers), with occasional Scrum Master responsibilities
Design and development of an Admin CA in Java to generate valid and invalid X.509, CVC G1, and CVC G2 certificates using Spring 2 and Bouncy Castle

Jul 2016 - Dec 2016

6 months

C++ developer in embedded environment

T-Systems

Implementation of control routines for card terminals using the SICCT protocol to communicate with smartcard crypto processors
Development environment: Eclipse, source code management with Git, ticket system Jira, documentation in Confluence
Development in a Scrum process, tests in Gherkin with Cucumber and programming of the Cucumber scanner routines in Java

Jul 2015 - Sep 2020

5 years 3 months

Managing director and developer

CSC

Design and development of the open source VelamentumServerSuite as a Docker container (12-factor app) for Intel and ARM hardware in a SOHO environment
Development of a VelamentumCA in Go for issuing and actively distributing valid X.509 certificates, support for SCEP and OCSP
Integration of OpenVAS, Snort, OSSEC, iRedMail, RoundCube, Rainloop, Nextcloud, OpenMediaVault and Kodi as apps
Use of Jira, YouTrack, Git, GitLab, Docker registry and Ansible for task management, versioning, image deployments and DevOps support

Nov 2013 - Jun 2015

1 year 8 months

Software architect and developer in PKI environment

gematik GmbH

Design and programming of a GematikCA for X.509 and CV certificates, extending and later fully replacing the open source EJBCA components with own source code
Web interface in HTML/CSS with jQuery
Core: Java library for generating valid and invalid certificates according to X.509, CV G1, CV G2 with Brainpool curves
Creation of valid and invalid TSLs, use of BouncyCastle for cryptographic routines
Project management with Maven and Ant, version control git/gitblit, Jira in an agile Scrum process

Jan 2010 - Oct 2013

3 years 10 months

Freelance software architect and developer

OpenLimit GmbH

Development of complex C++ and Java libraries for proprietary crypto software
Design of a signature service with RESTful interface for a browser-based client
Development of the web GUI in HTML/CSS, porting console functionality into a web application with over 100 adjustable parameters
Server-side JSF, database integration via JPA, communication with smartcards/HSMs via PKCS#11, version control with SCCS and Subversion

Oct 2009 - Jan 2015

5 years 4 months

Self-employed in crypto software design and sales

Self-employed

Design, development and sales of the Velamentum crypto software to protect computers against trojans
Design of a complex PKI with a central trust authority and smart card protection
Leading a team of one developer and one designer

Mar 2005 - Sep 2009

4 years 7 months

Programmer and Software Architect

Bundesdruckerei GmbH, Berlin

Design and programming of the Country CA for Germany to generate ICAO-compliant CV certificates for passports
Development of cryptographic routines with Bouncy Castle, GUI with SWT
Technical project management and implementation of a complex PKI

Jan 2005 - Feb 2005

2 months

Freelance Programmer

Bundesdruckerei GmbH, Berlin

Assisted in creating software to program the chips in electronic passports

Apr 2004 - Dec 2004

9 months

Author of technical book Applied Typography

Self-employed

Creation of a technical book on typography, type layout, and book printing techniques
Use of OpenOffice for prepress and professional typesetting

Apr 2002 - Mar 2004

2 years

Freelance Software Developer

Alcatel Berlin

Creation of a project study for internal communication between signal boxes (in English)
Implementation of the Euroradio protocol for the Alcatel/Siemens communications stack
Coding the communication between signal boxes using OpenSSL in C++
Design of a generic crypto communications stack and creation of test routines for SIL 4 approval by the Federal Railway Authority
Porting open-source software to a high-security hardware platform (Tagopert)
Working in a team of about 85 people

Apr 1997 - Feb 2002

4 years 11 months

Freelance Programmer

Self-employed

Programming in K&R C and C++ (MFC, STL) for retail (Lidl & Schwarz) and government agencies (BfA)
Code porting from C to C++ considering the Year 2000 problem

Industry experience

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Experienced in Information Technology, Government and Administration, Education, Retail, Healthcare, and Telecommunication.

Information Technology

Government and Administration

Education

Retail

Healthcare

Telecommunication

Business area experience

See which departments and functions this freelancer has contributed to most.

Experienced in Information Technology, Product Development, Project Management, Research and Development, Sales, and Operations.

Information Technology

Product Development

Project Management

Research and Development

Sales

Operations

Summary

28 years of experience in software architecture and development in general cryptographic programming (symmetric, asymmetric, cryptographic security for data transmissions, Public Key Infrastructures (PKI)) in C/C++, Java, Go, and Angular, design, programming, network design for secure operation of active malicious computers, development of a full-stack application with Angular as the frontend framework and Java and Go as backend languages, setup and operation of Certificate Authorities (CAs), penetration testing, project management for the “T-Systems Konnektor” product, collaboration with gematik on software and hardware specification for the “Elektronische Patientenakte” project, test developer for the KoCo connector, PKI software developer for HSM control from Java for key derivations, team member at Techniker Krankenkasse for requirements gathering of PKI security for the Techniker Krankenkasse mobile app.
25 years of experience in software architecture and development in C/C++ and Java on Windows, Linux, and AIX, including control of the operating systems' GUI implementations.
16 years of experience in Java programming:
Storing data via the JPA interface
Spring Boot 3 framework
JavaFX GUI applications
Application design with Java 6, 7, 8, 9, 11, 13, 18, 21, 24
Architecture and design development of complex server applications with RESTful APIs
Use of the Swagger OpenAPI framework
Extensive use of the Bouncy Castle library
JavaFX GUI development
13 years of experience using application servers JBOSS, Glassfish, and Wildfly.
10 years of experience with smart card interfacing, PKCS#7, PKCS#10, PKCS#11, and PKCS#15 APIs, interfacing from Java and C++, ISO 7816 tokens.
12 years of experience with HTTP and CSS, setting up projects with the Bootstrap framework and with Angular.
10 years of experience in web service technologies SOAP and RESTful services (via Java Spring and Java Spring Boot).
10 years of experience implementing Clean Code paradigms (after R.C. Martin) and SOLID principles in software, especially for loose coupling via interfaces and restricting responsibilities of Java classes.
7 years of experience working in Scrum teams as a developer (BITMARCK, Gematik, T-Systems) and as a software architect and team lead/PO (T-Systems).
5 years of experience programming web GUI applications with Angular, JavaScript, jQuery with AJAX, and client-side calls to RESTful services.
5 years of experience with Docker and Podman as tools for isolated application execution on a single machine and for support in rollout processes.
5 years of experience with SQL using MS SQL, MySQL, PostgreSQL from Java and Python (Django).
5 years of experience in application programming with libraries from OpenSwan, IPSEC, OpenVPN, CyberGhost, DNSSEC, ISO 7816 tokens.
5 years of experience using and writing plugins for the vulnerability scanner OpenVAS, registered as an open source developer at Greenbone since 05/2015.
2 years of experience in Python programming (Django and Python-based control of websites and databases).
5 years of experience using the DevOps software Ansible in the software development process.
6 years of experience with Maven, SVN, Git, GitLab, Jira, Confluence (also as administrator); IDEs: Eclipse, IntelliJ IDEA, IntelliJ Go, IntelliJ PyCharm, Visual C++, MPS.
3 years of experience driving the SICCT protocol in Java and C++.
3 years of experience creating, testing, and deploying Podman and Docker images to local registries, converting server software into 12-factor apps in Podman or Docker containers.
3 years of experience setting up and using local Podman and Docker registries (e.g., within GitLab), creating, testing, and deploying to local registries, converting server software into 12-factor apps in Podman or Docker containers.
2 years of experience implementing Domain Driven Design in Java, Go, and Angular.
3 years of experience implementing Behavior Driven Testing with Gherkin-based Cucumber for Go, Java, and TypeScript.
3 years of experience in frontend development with Angular 14, 15, 16, 17, 18, 19, 20, and 21.
4 years of experience in backend development with Go.
3 years of experience in GUI development with JavaFX 24 and 25.

Skills

Operating Systems: Unix/Linux (Ubuntu, Debian) +++ 26 Years.
Operating Systems: Windows (7, 8, 10, 11) +++ 25 Years.
Operating Systems: Mac Os (X) ++ 8 Years.
Operating Systems: Creating Custom Ubuntu Distributions ++ 6 Years.
Programming Languages/Frameworks: Java +++ 15 Years.
Programming Languages/Frameworks: C++ +++ 22 Years.
Programming Languages/Frameworks: C (Ansi C, K&R C) +++ 6 Years.
Programming Languages/Frameworks: Go +++ 5 Years.
Programming Languages/Frameworks: Angular +++ 3 Years.
Programming Languages/Frameworks: Typescript/Css/Html +++ 5 Years.
Programming Languages/Frameworks: Adminlte 3 For Angular +++ 5 Years.
Technologies: Uml +++ 13 Years.
Technologies: Domain Driven Design +++ 5 Years.
Technologies: Junit (Test-Driven Development) +++ 10 Years.
Technologies: Test Driven Design +++ 5 Years.
Technologies: Gradle +++ 6 Years.
Technologies: Webservices ++ 4 Years.
Technologies: Ansible +++ 6 Years.
Technologies: Javafx ++ 2 Years.
Technologies: Java Ee Technologies +++ 7 Years.
Technologies: Spring Boot 2 And Spring Boot 3 +++ 6 Years.
Technologies: Hsm And Smart Card Programming Via The Pkcs#11 Interface In Java +++ 7 Years.
Technologies: Cucumber With Java, Go, And Typescript +++ 5 Years.
Technologies: Selenium For Automated Web Testing +++ 5 Years.
Technologies: Evaluation Of Certificates According To The X.509 Standard +++ 9 Years.
Databases: Mysql/Mariadb ++ 5 Years.
Databases: Oracle ++ 2 Years.
Databases: Postgresql ++ 6 Years.
Tools: Wireshark ++ 5 Years.
Tools: Jetbrains Intellij Ultimate And Eclipse (Angular, Html, Css, C++, Java, And Go) +++ 11 Years.
Tools: Together +++ 3 Years.
Tools: Enterprise Architect +++ 3 Years.
Tools: Clearcase ++ 3 Years.
Tools: Svn +++ 5 Years.
Tools: Confluence +++ 11 Years.
Tools: Git +++ 10 Years.
Tools: Cryptographic Library Bouncy Castle +++ 10 Years.
Tools: Maven, Gradle, Groovy +++ 8 Years.
Tools: Cmake +++ 8 Years.
Tools: Make +++ 10 Years.
Tools: Jira +++ 5 Years.
Tools: Confluence +++ 5 Years.
Tools: Openproject + 1 Year.
Products: Ms Office (Macro Development) +++ 7 Years.
Products: Openoffice/Libreoffice (Macro Development) +++ 7 Years.
Miscellaneous: Communication Protocols Tls +++ 16 Years.
Miscellaneous: Preparation And Delivery Of Training In Cryptography, Office, And Pki +++ 13 Years.

Languages

German

Native

English

Advanced

Education

Sep 1990 - Mar 1997

University of Rostock

Diploma Engineer · Electrical engineering, specialization in communications engineering, focus on “Secure Data Transmission” · Rostock, Germany · 1.4

Oct 1987 - Jun 1989

Brinkmann-Gymnasium Güstrow

Abitur · Güstrow, Germany · 1.2

Certifications & licenses

Scrum.org

Statistics

Experience

Total positions 20

Experience in Information Technology 17 y

Avg length 2 y 6 m

Longest experience 7 y 8 m

Expertise

Recent roles IT Consultant in PKI Software Development, Software Architect (Subject Matter Expert), Freelance Java Developer

Main industries Information Technology, Government and Administration, Education

Main business areas Information Technology, Product Development, Project Management

Qualifications

Highest degree Bachelor

Certifications earned 2

Profile

Member since

February 2026

Last update

July 2026

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Frequently asked questions

Have questions? Find more information here.

Toralf is based in Hohen Neuendorf, Germany and can operate in on-site, hybrid, and remote work models.

Toralf speaks the following languages: German (Native), English (Advanced).

Toralf has at least 29 years of experience. During this time, Toralf has worked in at least 18 different roles and for 13 different companies. The average length of individual experience is 2 years and 6 months. Note that Toralf may not have shared all experience and actually has more experience.

Based on recent experience, Toralf would be well-suited for roles such as: IT Consultant in PKI Software Development, Software Architect (Subject Matter Expert), Freelance Java Developer.

Toralf's most recent position is IT Consultant in PKI Software Development at BWI.

In recent years, Toralf has worked for BWI, Techniker Krankenkasse, BITMARCK, Ingrano GmbH, and Velamentum.

Toralf is most experienced in industries like Information Technology, Government and Administration, and Education. Toralf also has some experience in Retail, Healthcare, and Telecommunication.

Toralf is most experienced in business areas like Information Technology, Product Development, and Project Management. Toralf also has some experience in Research and Development, Sales, and Operations.

Toralf has recently worked in industries like Information Technology, Education, and Healthcare.

Toralf has recently worked in business areas like Information Technology, Product Development, and Research and Development.

Toralf holds a Bachelor in Electrical engineering, specialization in communications engineering, focus on “Secure Data Transmission” from University of Rostock.

Toralf has 2 certificates. These include: Professional Scrum Product Owner and Professional Scrum Master.

The availability of Toralf needs to be confirmed.

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Daily rate avg. 975 €

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Median rate 1000 €

The median daily rate is the middle value of all daily rates — half of comparable freelancers charge less, half charge more. Unlike the average, it is barely affected by outliers.

Calculated based on our freelancers’ daily rates as of 2 Sep 2026. Actual rates may vary depending on seniority level, experience, skill specialization, project complexity, and engagement length.