PDF Auto-Sign System

Built two production signing services for an international Upwork client. Milestone 1: Flask API running as a Windows Service, signing PDFs via an Aruba CNS smart card (PKCS#11), with automatic failure handling, email alerts, and Adobe-verified output. Milestone 2: Same Flask API on Ubuntu via systemd, signing with a P12 certificate over WireGuard VPN + SSH. Both confirmed working — Adobe Reader shows "Signed and all signatures are valid."