HIPAA audited file proxy

The problem

Clinical documents needed authenticated, scoped, audited delivery between systems. Tokenized URLs were scoped too loosely; download paths bypassed virus scanning; retention rules varied by partner; the audit trail had gaps when documents arrived from third-party EHRs. An external HIPAA security audit was scheduled and the team needed compliance baked into the pipe.

The approach

We built a .NET file proxy: tokenized download URLs scoped to a single document, single recipient, single time window; virus scanning before delivery; configurable retention per partner contract; full audit trail logging every read, every download, every expiry. Integration adapters handle EHR and partner systems uniformly. The audit dataset is queryable for compliance review without exporting CSVs.

Stack and engineering choices

• .NET secure proxy
• Tokenized scoped URLs
• Virus scanning gate
• Configurable retention
• Per-document audit log
• EHR + partner adapters
• Compliance-ready audit dataset

Outcome

The proxy passed external HIPAA security audit on the first review without remediation. Token misuse is impossible by construction; retention is enforced by configuration; the audit dataset closes compliance questions in minutes instead of weeks.