Stefan Guilhen
Principal Software Engineer at IBM
São Paulo, Brazil
Summary
🤩
Rockstar🎓
Top SchoolStefan Guilhen is a Principal Software Engineer with 16 years of experience specializing in backend systems and security, now based in São Paulo and currently at IBM after a long tenure at Red Hat. He holds an M.Sc. in Computer Science with a security focus from USP and has deep expertise implementing authentication, authorization and cryptographic integrations in enterprise Java stacks. An active open-source contributor, Stefan has materially advanced WildFly and Elytron security—adding BCrypt/SCRAM password types, Kerberos enhancements, and Elytron-based quickstarts that demonstrate SSL and mutual-SSL deployments. His work spans core runtime changes, JacORB subsystem integrations, and permissions-validation phases, reflecting a knack for improving both developer experience and production security. Colleagues know him for reducing duplication through thoughtful refactors and for translating complex security protocols into practical, deployable examples. He combines academic depth with hands-on server-side craftsmanship, often surfacing non-obvious interoperability fixes that prevent subtle authentication failures in large deployments.
16 years of coding experience
18 years of employment as a software developer
M.Sc, Computer Science - Security, M.Sc, Computer Science - Security at Universidade de São Paulo / USP
Github Skills (29)
jboss-eap10
authorizations10
ssl10
tls1210
jaas10
corba10
kerberos10
user-authentication10
authentication10
tls1310
java10
security-protocol10
security10
javas10
security-policy10
Programming languages (6)
Github contributions (5)
wildfly/wildfly
Oct 2012 - May 2015
WildFly Application Server
Role in this project:
Back-end Developer
Back-end DeveloperContributions:8 commits, 16 PRs, 23 comments in 2 years 7 months
Contributions summary:Stefan primarily worked on the JacORB subsystem, focusing on implementing and integrating various components. Their contributions involved integrating JacORB with other elements, implementing subsystems, and fixing description providers. The user made enhancements to existing features and added new functionality. These changes involved modifications to various Java files within the jacorb directory.
javawildflydockerapplication-server
wildfly-security/wildfly-elytron
Jul 2014 - Feb 2018
WildFly Elytron: Security, Authentication, and Authorization SPIs for the WildFly project
Role in this project:Back-end Developer & Security Engineer
Back-end Developer & Security EngineerContributions:85 commits, 80 PRs, 69 pushes in 3 years 8 months
Contributions summary:Stefan primarily contributed to the implementation of security-related features within the WildFly Elytron project. Their work involved creating and modifying password implementations, specifically focusing on BCrypt and ScramDigest password types. The user also refactored code to avoid duplication and added enhancements to the JaasSecurityRealm and Kerberos integration, demonstrating expertise in security protocols and authentication mechanisms.
wildflyauthorizationsecurityauthenticationelytron
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