KyeongSeob Sim
KyeongSeob Sim
Software Developer

About Me

I’m a software developer who likes traveling and photography, coffee and books.
I like Linux and python, and I’m interested in automation, non-binary code and system architecture.
I want to write code like writing, and I don’t like inefficient, unproductive things.
I’m interested in new technologies and languages. And I’m also interested in improving the inconvenience of working with developers.
I want to develop a program for a long time. :)

Professional Experiences (8Y ~ )

Texada Software

  • Senior Developer (2019/06 ~ )
    • Role
    • Experience

Penta Security System (7Y 6M)

  • IoT bussiness related demonstration program development (2018/06 ~ 2019/05)
    • Role
      • Head of V2G PnC product development.
      • Development of security and test environment for electric vehicle charging infrastructure.(PnC)
      • Development of demonstration program for vehicle related business.
    • Experience
      • Mobile Bluetooth smart key (Andorid App) development for demonstration with security.
      • Development of security test environment for electric car charging process. (PnC)
      • Development of TLS library to be embedded in EV. (Electric Vehicle)
      • Development of web scraping service to get announcements of national organizations related to vehicle business.
      • Development of certificate issuing web service according to ISO 15118. (Called AmoCA)
  • Infrastructure development (2018/01 ~ 2018/05)
    • Role
      • Team Manager
      • Deployment and development of in-house OS, API and libraries.
      • Development of in-house common infrastructure (Hardware, Virtualization).
    • Experience
      • Developed daemon, API, libraries included in OS (Network, Resource, Bypass, SNMP, etc…).
      • Develop packages and libraries for in-house OS based on debian.
      • New CLI development included in in-house OS using Python.
      • New in-house OS design and development with enhanced security.
      • Internal interface design of in-house OS using D-bus and REST API.
      • Debian APT server management.
      • Build in-house docker registry.
      • Server hardware, bypass/NIC/RAID drivers management based on intel.
      • Support domestic CC certification.
  • Detection engine development (2017/08 ~ 2017/12)
    • Role
      • Maintain detection engine of WAPPLES (WAF).
      • WAPPLES’s (WAF) new detection engine development.
    • Experience
      • Improvement of file upload function of detection engine.
      • Improvement of packet test simulator of detection engine.
      • Development of access control function of detection engine.
      • Enhanced handling of each large packet for normal(content-length), chunked, multi-part.
      • Improved session handling and interface enhancement.
  • Foundation development (2016/01 ~ 2017/07)
    • Role
      • Team Manager
      • Debian and Gentoo Linux management and deployment.
      • WAPPLES (WAF) create and deploy integrated packages.
      • WAPPLES (WAF) based daemon, CLI development and management.
    • Experience
      • Porting a Debian6(kernel 2.6.32) based kernel to Debian8(kernel 3.16).
      • WAF support for AWS and MS-Azure, Google Cloud Platform and IBM Softlayer.
      • Deployment and advancement of in-house OS based on debian.
      • Development of base daemon used in WAF (Network, Resource, Bypass, SNMP, etc…).
      • Process improvement inside WAF (initd -> systemd / socket based -> d-bus).
      • Build in-house debian package server(APT).
      • Development of functions for domestic CC certification(Korea).
      • Server hardware, bypass/NIC/RAID drivers management based on intel.
      • Development of WAF performance measurement automation program for Avalanche3100 using Jenkins and TCL.
      • OpenVPN based SSL VPN product development and domestic CC certification support.
  • Network platform development (2013/11 ~ 2015/12)
    • Role
      • WAPPLES (WAF) TCP acceleration module and daemon development.
      • Custom linux development and security patch for TCP acceleration module.
      • Intel-based hardware management and performance measurement.
    • Experience
      • Maintaining thg WAF TCP acceleration kernel module.
      • Development of IPv6 support function of TCP acceleration module.
      • Development of TCP packet processing simulator.
      • Development of integrated package automation test framework using Python, Bash-shell, Jmeter and Jenkins.
      • Gentoo-based custom kernel and kernel modules, drivers maintenance.
      • Debian-based custom kernel development and Gentoo porting.
      • CLI and daemon development related to function setting.
      • Server hardware, bypass/NIC/RAID drivers management based on intel.
      • Support for virtualization environments such as Hyper-V, RHEL and KVM.
      • Measure and manage performance with Avalanche2900/3100, Breaking Point.
  • UX development (2012/01 ~ 2013/10)
    • Role
      • GUI development of next WAPPLES (WAF).
    • Experience
      • Maintaining the WAF GUI using C#, .Netplatform and PostgreSQL.
      • WAF GUI development using C# and .Netplatform.
      • DB interface development of MariaDB and CouchDB.
      • Build GUI build and test automation using TestComplete, Python.
      • International CC certification.
      • Investigate obfuscation methods for code security in the WAF GUI.

ENTO Networks (1Y)

  • VPN development (2011/01 ~ 2011/12)
    • Role
      • Development of debian-based VPN packet processing server.
      • Windows XP and Win7 based client and network driver development.
    • Experience
      • Development of VPN packet processing server using netfilter library and C.
      • Maintain Windows XP client with WinAPI and C.
      • Win7 based client development using C# and .Netfraemwork.
      • Deveopment of Windows XP driver using “passthru” of DDK NDIS.
      • Developemtn of Win7 packet processing driver using WDK NDIS.

Technical Skills

  • Languages
    • Proficient : C/C++, Python, Shell
    • Prior experiences : Java, PHP, Kotlin, Javascript, C#, Swift, Ruby
  • Service & Applications
    • Building experience : Jenkins, Gerrit, MediaWiki, Redmine, iceScrum, Mantis
    • PKI, CLI, Systemd, D-bus, Memcached, Proc system
  • Platforms
    • Linux
      • Debian, Ubuntu, Gentoo, CentOS, Raspbian
      • Specially Debian
    • Linux Kernel Module/Drivers
      • i2c, pmbus
      • Network & Bypass based on intel.
    • Librarys & Frameworks
      • Apache2, Nginx, Django, Node.js, Laravel
      • Mysql, MariaDB, PostgreSQL, CouchDB, Sqlite
    • Windows (Unfamiliar)
      • Windows XP, Win7
      • WinAPI, .NetPlatform, WDK, NDIS
  • Infrastructures
    • Virtualization
      • AWS, MS Azure, Google Platform, IBM Softlayer
      • RHEL, KVM, Hyper-V, Xen, vSphere
    • Docker & Docker Registry
    • Debian APT(Advanced Packaging Tool) Server
  • Development Methodologies
    • Agile, Scrum, Kanban, Lean
    • iceScrum, Asana, Trello, Redmine, Mantis
  • Etc
    • Hardware Test Devices
      • Avalanche2900, Avalanche3100
      • Breaking Point
    • Hardware
      • Caswell’s intel based server.
      • Raspberry Pi, Arduino
      • Nordic PCA10040 (BLE, uart)


  • Engineer Information Processing
    • HRD Korea (Human Resources Development Service of Korea)
    • 2012/06/01
  • SIS (Specialist for Information Security) Level 2
    • KISA (Korea Internet Secuirty Agency)
    • 2011/08/11
  • Linux Master Level 1
    • KAIT (Korea Association for ICT Promotion)
    • 2011/05/13


  • Gachon University (2009 ~ 2016)
    • Bachelor of Engineering (B.E), Computer Science (CS)
    • Grade : 4.19 / 4.5
    • Club
      • GNU Zone - Linux academic club
      • Defender - Information security club
      • KUCIS - Korea university clubs information security