Encryption in transit

Protect the journey between systems

Data is in transit when a browser loads a client record, a mobile app sends session data, an API moves an authorization, an employee connects remotely, or a vendor receives a backup. Transport encryption protects that journey. Encryption at rest protects stored data.

The distinction matters because one record may be protected in storage and exposed while moving. It may also travel safely and then land on an unmanaged device. Owners need controls for the complete path.

Inventory paths before choosing technology

Create a transmission register that records:

• sending and receiving systems, owners, vendors, and environments
• data categories, including whether ePHI or other sensitive data is present
• protocol, certificate, authentication, integrity, and key details
• user, service-account, and application authorization
• expected frequency, route, failure handling, logging, and retention
• current test evidence, exceptions, compensating measures, and review date

Include email, portals, file transfers, interfaces, telehealth, texting, remote support, device synchronization, print vendors, clearinghouses, and internal network segments. A vendor questionnaire cannot reveal a forgotten spreadsheet upload.

TLS is a common transport control

Transport Layer Security, or TLS, can authenticate endpoints and protect confidentiality and integrity during network communication when it is selected and configured correctly. Protocol version, certificates, cipher configuration, hostname validation, trust stores, and downgrade protection all matter.

NIST SP 800-52 Rev. 2 is final guidance for federal TLS implementations. It discusses TLS selection, configuration, certificates, and extensions. A private ABA practice can use its concepts as technical guidance. The publication does not certify a vendor or create one universal configuration for every product.

HIPAA requires a documented evaluation

For covered entities and business associates, current 45 CFR 164.312(e) requires technical security measures against unauthorized access to ePHI transmitted over electronic networks. Integrity controls and encryption are addressable implementation specifications.

Addressable means the regulated entity evaluates whether the specification is reasonable and appropriate, documents its decision, and implements an equivalent alternative when appropriate. HHS email guidance says open-network transmission can occur when ePHI is adequately protected. This analysis is broader than checking whether a browser displays a lock icon.

A fictional path review

Nora's multi-site practice locks a due cohort of 24 transmission paths. Twenty-one have current evidence for protocol, endpoint identity, access, certificate monitoring, logs, vendor responsibility, and failure handling: 21 of 24, or 87.5%.

One legacy file transfer uses an expired exception. Two interfaces lack verified receiver identities after a vendor change. All three remain open with owners, safe interim routes, and dates. The percentage measures evidence completeness, not security or HIPAA compliance.

Test the deployed connection

Review documentation and then test the real path. Confirm the intended receiver, current certificate, approved protocol, refusal of unsafe connections, integrity behavior, access permissions, audit events, error alerts, retry logic, and data received. Use authorized test data.

Test from representative devices, networks, environments, and integration routes. An interface may be secure in production and weak in a test environment that still contains client information. Monitor certificate expiration, configuration drift, new endpoints, failed handshakes, and unusual destinations.

Review common failure patterns

Certificate expiration can stop a valid connection. Weak hostname validation can connect to the wrong endpoint. A reverse proxy may encrypt the public leg and send plain traffic across an internal segment. Logs can accidentally store complete payloads. Staff may download an encrypted transfer onto an unmanaged device. Retry logic may route data through an unapproved destination.

Trace every leg rather than assuming one secure endpoint covers the path. Include load balancers, gateways, message brokers, vendor support tools, mobile synchronization, and downstream storage. Give certificates and keys named owners, monitored expiration dates, approved issuance and rotation processes, and tested revocation. Review changes to domains, network architecture, vendors, and integrations before release.

Keep endpoint and workflow controls

Transport encryption does not determine who should see the data, whether the disclosure is permitted, whether the recipient stores it safely, or whether the record is accurate. Pair it with identity, least-privilege access, approved devices, logging, malware protection, retention, vendor controls, and staff procedures.

Plan for failures. A secure channel outage should lead to a defined hold, approved alternate route, or safe downtime process. Staff should know which consumer messaging, personal email, removable media, and copy-and-paste routes are prohibited or restricted.

The NIST Cybersecurity Framework 2.0 can organize identification, protection, detection, response, and recovery work. It is voluntary general guidance rather than evidence that a transmission is compliant or safe.