During my career at IBM I have worked in the z/OS (mainframe) security area as a software engineer, developer, and designer for the IBM Tivoli Directory Server (TDS) for z/OS and the z/OS System SSL products. Key accomplishments:- Technical owner of the IBM TDS manuals where I oversaw the writing of a new manual for return codes and messages. This effort led to a reduction in calls to the customer support center. - Presented at several conferences such as RACF User's Groups, SHARE and z/OS Teach the Teachers.- Lead Level 3 service developer on IBM TDS where I was responsible for ensuring that fixes in the service stream met IBM's high quality standards.- Assisted with a major rewrite of the code base for the IBM TDS for z/OS. The rewrite greatly improved the reliability, availability, and serviceability of the product along with adding new features that were not present in the original z/OS LDAP server.- Enhanced z/OS System SSL by delivering TLS (Transport Layer Security) V1.2 support to an in-service release.- Greatly improved the certificate revocation support in z/OS System SSL to allow OCSP (Certificate Status Protocol) responders and HTTP servers for CRL (Certificate Revocation Lists) to be contacted for revocation status.- Augmented z/OS V2R3 System SSL to be compliant with the latest certificate and handshake related standards for Suite B (Request For Comments (RFCs) 5759 and 6460), OCSP (RFC 6960), OCSP Stapling (RFCs 6066 and 6961), and SCSV (Signaling Cipher Specification Value) protocol fallback detection (RFC 7507)- Architected the implementation of TLS 1.3 within z/OS V2R4 System SSL- Implemented extended master secret support for TLS 1.2 and earlier protocols