Toralf Chryselius
IT Consultant in PKI Software Development
Experience
IT Consultant in PKI Software Development
BWI
- Implementation of a full-stack application with Angular as front-end framework and Java as back-end language
- Use of the Swagger OpenAPI specification for REST communication between front-end and back-end applications
- Control of a card printer via the Nexus Card SDK framework
- Design and implementation of card management software with web interface and JavaFX module for printer monitoring
- Use of Cucumber tests for test automation and creation of test artifacts for testing 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
IT Consultant in PKI Software Development
BWI
- New development of existing software with 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
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 focus on vaccine individualization
- Creation of Scrum stories and acceptance criteria for bug fixes and new features
Freelance Java Developer
BITMARCK
- Development of software for describing health data for health insurers on JBOSS servers with J2EE
- Use of the BDD language Gherkin in Cucumber for end-to-end tests with Selenium for the web interface under Java
- Implementation of Clean Code principles and loose coupling between frameworks
Freelance Java and Groovy Developer
Ingrano GmbH
- Further development of existing tests for Worldline GmbH
- Addition of features to the cryptolib for generating RSA and ECC certificates in the X.509 area
- Revision of test design according to Clean Code paradigms
Freelance Test Developer
Ingrano GmbH
- Adapting and developing new tests for the KoCo connector based on field test errors and TÜV IT requirements
- Testing the cryptographic parameters of secure data transmission between the connector and the healthcare telematics infrastructure
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 issue 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 custom-designed containers
- Creation of a training course with hardware (Raspberry Pi 5 or AMD64 machine) and training materials for practical network security
Specification Engineer in the Patient Team
gematik GmbH
- Further development of the specification for the architecture of the electronic patient record (ePA)
- Management of the requirement lifecycle (AFOs) for ePA versions 1 through 5
- Implementation of fine-grained access control according to the Patient Data Protection Act in the software architecture
- Close coordination with specifiers of other components, ensuring technology neutrality and compatibility
Lecturer in Computer Security, Penetration Testing and IT System Security
Code University Berlin
- Designing and delivering a block seminar in English
- Building 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 orchestration of Metasploit, ZenMap, Armitage, OpenVAS, Snort, OSSEC and Graylog for hands-on training in attacks and monitoring
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), occasionally taking on Scrum Master tasks
- 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 BouncyCastle
C++ Developer in Embedded Systems
T-Systems
- Implementation of control routines for card terminals using the SICCT protocol to communicate with smart card 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 Cucumber scanner routines in Java
Managing Director and Developer
CSC
- Design and development of the open source VelamentumServerSuite as Docker containers (12-factor app) for Intel and ARM hardware in SOHO environments
- Development of a VelamentumCA in Go for issuing and actively distributing valid X.509 certificates, supporting 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, version control, image deployments, and DevOps support
Software Architect and Developer in the PKI Environment
gematik GmbH
- Design and implementation of a GematikCA for X.509 and CV certificates, extending and later completely replacing the open source EJBCA components with custom 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 Bouncy Castle for cryptographic routines
- Management with Maven and Ant, version control with git/gitblit, Jira in an agile Scrum process
Independent Software Architect and Developer
OpenLimit GmbH
- Development of complex C++ and Java libraries for proprietary cryptographic software
- Design of a signature service with a RESTful API for a browser-based client
- Development of the web GUI in HTML/CSS, porting the console functionality to a web application with over 100 configurable parameters
- Server side: JSF, database connection via JPA, communication with smart cards/HSMs via PKCS#11, version control with SCCS and Subversion
Commercial Self-Employment in Crypto Software Design and Sales
Self-Employed
- Design, development, and distribution of the crypto software Velamentum to protect computers against Trojans
- Design of a complex PKI with a central trust authority and smart card security
- Leading a team of one developer and one designer
Programmer and Software Architect
Bundesdruckerei GmbH, Berlin
- Design and programming of the country CA for Germany to create 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
Freelance Programmer
Bundesdruckerei GmbH, Berlin
- Contributed to the development of software for programming chips in electronic passports
Author of a technical book on applied typography
Self-Employed
- Created a technical book about typography, page layout, and printing techniques
- Used OpenOffice for prepress and professional typesetting
Freelance Software Developer
Alcatel Berlin
- Developed a project study on internal communication between signal boxes (English)
- Implemented the Euroradio protocol for the Alcatel/Siemens communication stack
- Coded communication between signal boxes using OpenSSL in C++
- Designed a generic crypto communication stack, created test routines for SIL 4 certification at the Federal Railway Authority
- Ported open-source software to a high-security hardware platform (Tagopert)
- Worked in a team of about 85 people
Freelance Programmer
Self-Employed
- Programming in K&R C and C++ (MFC, STL) for retail (Lidl & Schwarz) and government agencies (BfA)
- Ported code from C to C++ with consideration of the Year 2000 problem
Industries Experience
See where this freelancer has spent most of their professional time. Longer bars indicate deeper hands-on experience, while shorter ones reflect targeted or project-based work.
Experienced in Information Technology (16.5 years), Government and Administration (10.5 years), Education (7 years), Retail (5 years), Healthcare (4.5 years), and Telecommunication (2 years).
Business Areas Experience
The graph below provides a cumulative view of the freelancer's experience across multiple business areas, calculated from completed and active engagements. It highlights the areas where the freelancer has most frequently contributed to planning, execution, and delivery of business outcomes.
Experienced in Information Technology (27.5 years), Product Development (24 years), Project Management (12.5 years), Research and Development (7 years), Sales (5.5 years), and Operations (5 years).
Summary
28 years of experience in software architecture and development in general cryptography programming (symmetric, asymmetric, cryptographic securing of 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 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 at gematik on software and hardware specification for the "Electronic Health Record" project, test developer for the KoCo connector, PKI software developer for HSM control from Java for key derivations, staff member at Techniker Krankenkasse for requirements gathering for PKI security of the Techniker Krankenkasse mobile app.
25 years of experience in software architecture and development in C/C++ and Java programming on Windows, Linux and AIX, including GUI integrations of the operating systems.
16 years of experience in Java programming:
Storing data via the JPA interface
Spring Boot 3 framework
JavaFX GUI applications
Application design in Java 6, 7, 8, 9, 11, 13, 18, 21, 24
Development of architecture and design of complex server applications with RESTful API
Use of the Swagger OpenAPI framework
Extensive use of the Bouncycastle library
JavaFX GUI development
13 years of experience using application servers JBOSS, Glassfish and Wildfly.
10 years of experience in smart card control, PKCS#7, PKCS#10, PKCS#11 and PKCS#15 API, control from Java and C++, ISO 7816 token.
12 years of experience in HTTP and CSS, setting up projects with the Bootstrap framework and with Angular.
10 years of experience in web service technologies SOAP, RESTful service (via Java Spring and Java Spring Boot).
10 years of experience implementing Clean Code paradigms (by R.C. Martin) and SOLID principles in software, especially for loose coupling via interfaces and single responsibility of Java classes.
7 years of experience working in Scrum teams as developer (BITMARCK, gematik, T-Systems) and as software architect and team lead PO (T-Systems).
5 years of experience programming WebGUI applications with Angular, JavaScript, jQuery with AJAX and client-side control of RESTful services.
5 years of experience with Docker and Podman as a tool for isolated execution of applications on a machine and to support deployment 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 token.
5 years of experience using and plugin programming of vulnerability scanner OpenVAS, registered open source developer at Greenbone since 05/2015.
2 years of experience in Python programming (Django and Python control of web pages and databases).
5 years of experience using the DevOp 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 GoLang, IntelliJ PyCharm, Visual C++, MPS.
3 years of experience controlling the SICCT protocol in Java and C++.
3 years of experience creating, testing and deploying Podman and Docker images in local registries, converting server software to 12-factor apps within 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 in local registries, converting server software to 12-factor apps within Podman or Docker containers.
2 years of experience implementing Domain Driven Design in Java, Go and Angular.
3 years of experience implementing Behaviour Driven Testing with Gherkin styles using Cucumber for Go, Java and Typescript.
3 years of experience in front-end development with Angular 14, 15, 16, 17, 18, 19, 20 and 21.
4 years of experience in back-end 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: Creation Of 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: Admin Lte 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: Java Fx ++ 2 Years.
Technologies: Java Ee Technology +++ 7 Years.
Technologies: Spring Boot 2 And Spring Boot 3 +++ 6 Years.
Technologies: Hsm And Smart Card Programming Via 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: Analysis Of Certificates According To 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: Bouncy-castle Crypto Library +++ 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 Creation) +++ 7 Years.
Products: Openoffice/libreoffice (Macro Creation) +++ 7 Years.
Other: Communication Protocols Tls +++ 16 Years.
Other: Preparation And Delivery Of Training In Cryptography, Office And Pki +++ 13 Years.
Languages
Education
Universität Rostock
Diploma Engineer · Electrical Engineering, specialization in Communications Engineering, focus on "Secure Data Transmission" · Rostock, Germany · 1,4
Brinkmann-Gymnasium Güstrow
Abitur · Güstrow, Germany · 1,2
Certifications & licenses
Professional Scrum Product Owner
Scrum.org
Professional Scrum Master
Scrum.org
Profile
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