Introduction

I am Juan F. Capristán W., Fullstack Developer specialized in web development, in systems administration, and in blockchain technology. In 2022 I got interested in quantum computing and post-quantum cryptography, and went through some trainings on the topic.

I like working in projects focused in creating a better society whenever possible.

I like to program using Ruby, Rails, Sinatra, Golang, Gin and Python, though I also develop using node.js if unavoidable ;).

I am co-founder of CreativeCocos.com, and author of Bitcoin Boom! (in spanish).

If you want to contact me, the easiest way is writing me an email to juan@el placer de compartircreativecocos.la alegría de vivircom, or following me at Twitter (yes, Twitter).

Quick Look

• Juan Fernando Capristán Wadsworth
• I have knowledge on the impact and adoption of post-quantum cryptography in modern systems.
• I am familiarized with the PQC standardized by NIST algorithms, and its application in real environments.
• I have practical knowledge about the transition and compatibility towards post-quantum criptography.
• I am a Blockchain Architect
• I am a Distributed Applications (Dapps) Developer
• I am a Fullstack web developer
• I wrote "Bitcoin Boom!" book, available in Bubok, Kobo and Amazon (only in spanish)
• I love developing with Ruby on Rails, and also with Golang
• I speak spanish and english
• I live in Madrid
• juan@la alegría de vivircreativecocos.el placer de compartircom
• @jfcapristan
• My Linkedin profile
• My blog (in spanish)
• CreativeCocos

Studies

• Computer Science at U.C.M.
• English in P.U.C.P.

• Fundamentals of Encryption & Quantum-Safe Techniques. IBM - Cognitive Class. 2025
• ETHCC 8. Cannes, 2025
• ETHCC 7. Brussels, 2024
• Ethereum Devcon VI. Bogotá, 2022
• Practical Bootcamp in Blockchain Technologies. Devacademy. 2018
• RPA course with Kryon Studio. AG Software. 2018
• OpenExpo Europe 2017
• Ethereum Dapps Development with Solidity. KSchool. 2017
• Introduction Course to Blockchain Technology. KSchool. 2017
• BARUCO 2013. Barcelona Ruby Conference, Septiembre 2013.
• BARUCO 2012. Barcelona Ruby Conference, Septiembre 2012.
• "Internet Congress 2010". Madrid, October 2010.
• "IInd Webmasters Congress". Madrid, November 2008.
• "Internet Forum 2008". Madrid, May 2008.
• "IInd Congress of editors of periodical publications". Benidorm, March 2006.
• "Ist Congress of editors of periodical publications". Salamanca, February 2005.
• "Interñet : The future of spanish in the internet". Summer Courses in El Escorial, UCM. August 2003.
• "Electronic business, present and future". Summer Courses in UNED. July 2003.

Languages

• Spanish. Mother tongue
• English. Spoken, read and written
• German. Learning in progress...
• Esperanto. Learning in progress...

Programming Languages and Frameworks

• Solidity
• Golang
• Gin Framework
• Ruby + Rails
• Ruby + Sinatra
• python
• nodejs
• PHP + Yii
• React JS
• Vue JS
• jQuery
• Bootstrap
• LESS, SASS
• HAML, HTML5, HTML4, XML, XSLT, CSS3, CSS2
• JavaScript
• VBScript
• ASP.NET
• C#
• Classic ASP

Databases

• CouchDB
• MySQL Client and server administration.
• SQLite
• PostgreSQL
• MariaDB

The Internet

• Web applicaion development based on Gin / Golang.
• Web application development based on Sinatra.
• Web application development based on Ruby on Rails.
• Web application development based on PHP + Yii Framework.
• Web application development based on classic ASP.
• Skilled in HTML, CSS and Javascript, jQuery, ajax, bootstrap.
• Frontend development based on AngularJS.
• Website and blog development based in Jekyll.
• Installation and support on Wordpress, Joomla and other popular freeware CMSs systems.
• Installation and support on Prestashop for online stores.
• Installation and support for OpenX and Revival ad servers.
• Installation and support on Wiki systems like DokuWiki or MediaWiki.
• Secure payment interfaces of several spanish banks.
• PayPal and Stripe payment systems integration.
• nginx web server administration.
• Apache web server administration.
• IIS web server administration.

Blockchain

I have experience developing and administering public as well as private blockchain networks, as Ethereum or Fabric.

I have experience with the main tools used in Solidity development, such as: Remix, Etherscan, Blockscout, Metamask, Foundry, HardHat, Openzeppelin, etc.

• Ethereum + Solidity
• Hyperleger Fabric + Go
• Hyperleger Fabric + nodejs
• Hyperledger Besu
• Quorum

Cloud

• Docker
• Kubernetes
• Openshift
• Amazon Web Services (AWS)
• Azure Cloud
• Heroku (Rails Apps)

Organization

• Confluence
• Todoist/Wedoist
• Basecamp
• Eventum
• Mantis
• Bugzilla

• Git (Github, Gitlab, Bitbucket)
• Git Flow
• Mercurial

Experience

• I've been collaborating since 2022 with the Quantum Threat Group in Santander Bank, doing several kinds of tasks, as for example analysis of the new PQ algorithms, analysis of new tools, etc., related with the quantum threat to cryptography in the upcoming years.
• Currently I'm working on Santader Bank's Crypto Domain, in Madrid, as a Blockchain Architect
• I worked for Inetum Spain (ex Gfi) as Blockchain Consultant from 2018 to 2021.
• I am co-founder of web develpment company CreativeCocos.com and also of its social branch SocialCocos.
• I have developed project Tunaturopataonline, an online platform for a naturopathy cabinet.
• I have developed project Pildorea, an online education platform based on videos.
• I have developed DíayHora, an online reservation system aimed for both professionals and end users.
• I have developed EditMaker project for Cibeles.net, where I worked until december 2012. EditMaker is a web based CMS (Content Management System) aimed to newspapers or periodic publications in the internet. This product is being used by more than a hundred online publications.
• I have developed "CruciSolutions" project, which is a web based crosswords management system that can generate different kinds of similar games of this kind (with inner numbers, outer numbers, blank crosswords and also sudokus), for Puzzlecross S.L.
• I have developed a campaign generator for online signing for Veterinarios Sin Fronteras.
• I have developed project "en.via" (word game that means 'send' and also 'on the way'), which is an application to manage courier companies. This product is being used by EuroVip Service.
• Between 2004 and 2005 I have actively taken part on development of nofumadores.org (nonsmokers) organization website.
• I worked as a teacher in Maths informática academy, specialized in computer science carreer, teaching "Data Structures", "Introduction to Pascal Programming" and "Programming in C and C++" subjects. I taught for this academy between september 2000 and february 2002.
• Several minor freelance projects.

• Co-administrator of the Asamblea del Pueblo de Alpedrete Blog during more than 4 years (between 2011 and 2015)
• Designer of latin american newspaper Quipu during 8 months (between 1998 and 1999)
• Designer of legal magazine DINATOS between january 2000 and may 2001.

Other Info

• I have 23 years of professional experience
• I started the adventure of kids in 2012, and repeated in 2020.
• I like writing, reading, sports, and traveling.
• I am a self-tought piano player apprentice thanks to first lockdown in march 2020, and I've not stopped playing since then.
• I despice animal mistreat in any of its several forms. Specially those socially accepted.
• I was an active member of 15M movement (aka "occupy movement" in Spain) since its very begining in 2011, during 5 years. I think a good path to build a better society is partaking democracy, as the next logical step to the current representative model.
• I am interested in nature, sustainability, healthy life and alternative therapies.
• I don't like to be a passive smoker. Fortunately in Spain this is not a problem anymore (it took hard to get there).
• I believe in God, but absolutely not in religions.

Cryptography

I am not an expert in the matter, but I have knowledge of several tools related with this topic, directly or indirectly, as:

• PQ Cryptography algorithms (NIST compliant)
• Quantum Computing basics
• PKI tools (Let's encrypt, Certbot)
• Certificate Management
• Key Management
• SSL (OpenSSL)
• SSH