Quantum-Resistant Security Puts Healthcare and OT Device Fleets to the Test

Quantum readiness is becoming an equipment and data-flow problem for healthcare and other operational technology operators. Patient records can remain sensitive for years, while the medical and industrial devices that move them may need manufacturer firmware updates, compatibility checks, or recertification before they can use post-quantum cryptography (PQC). That mismatch gives security teams a practical reason to act before quantum computers can break current public-key cryptography.

The immediate concern is “harvest now, decrypt later” (HNDL): an attacker captures encrypted traffic today and keeps it in case future quantum computers can decrypt it. A Forescout report on more than 2.5 million devices across over 50 organizations examines the exposure in healthcare, where medical histories, scans, and lab results may retain their confidentiality value long after transmission.

Protect the full path, not just the database

Patient data moves through a chain of systems. A CT scanner may send images to a picture archiving and communication system (PACS), which can then share them with another hospital, a cloud service, or an outside radiology provider. Prescriptions and laboratory results follow their own routes through clinical platforms, providers, pharmacies, and other services. Each transfer can create another place where sensitive traffic may be intercepted.

Potential interception points include the medical device, an internal network, an edge router or firewall, and telecommunications infrastructure. Patient-record platforms can also be reachable from the public internet. In a Shodan search, Forescout found more than 5,500 internet-exposed medical information system instances. Electronic medical record platforms accounted for 46% of those instances and PACS for 40%.

Protocol support offers one indicator of migration readiness, but it does not prove that a connection is quantum-safe. Forescout found TLS 1.3 support in 36% of PACS, 33% of electronic medical record systems, and 13% of laboratory information management systems. TLS 1.3 is the only version of the protocol that supports ML-KEM, the Module-Lattice-Based Key-Encapsulation Mechanism standard published by NIST. Even when both endpoints support TLS 1.3, they may negotiate a different cryptographic algorithm.

The same gap appears in device software. In a June study, Forescout reported that 11.8% of internet-facing SSH servers were PQC-capable. The share fell to 3% for Dropbear, a server commonly found on embedded devices. Within enterprise networks, 50% of IT devices used OpenSSH versions with PQC support, compared with 28% of IoT devices, 16% of OT devices, and 6% of internet of medical things devices.

Those figures matter because cryptography in healthcare protects more than stored records. It can secure commands sent to devices, telemetry used for diagnosis, medication orders, and other exchanges. Forescout’s researchers warn that quantum-related attacks could enable unauthorized remote access by exploiting public-key authentication, tampering with device communications, or malware that abuses firmware integrity signatures. Their assessment is that PQC migration in healthcare is tied to patient safety as well as confidentiality.

Firmware turns migration into an operational project

For a live server, adopting a new cryptographic algorithm may be a library upgrade and a configuration change. Embedded equipment is a different case: it may require a complete firmware update from its manufacturer. Operators also need to preserve compatibility with systems that will not be upgraded at the same time. For certified medical devices, a change may require recertification.

Daniel dos Santos, Forescout’s vice president of research, says changing a device’s filesystem independently can jeopardize its certification, maintenance, and support, even where a technical workaround exists. Protocol changes must also preserve connections with other equipment. Those constraints apply well beyond hospitals, including chemical plants, electricity networks, water treatment facilities, and factory floors.

Some medical and industrial devices run Linux, which could make PQC adoption more feasible in principle. Dos Santos says he has seen little discussion of adoption plans or roadmaps among OT vendors. Forescout’s researchers warn that, at the current pace, specialized equipment is unlikely to complete migration this decade. Medical devices face particularly low adoption and difficult upgrade paths.

Guidance timelines can create a misleading sense of distance. The G7 Cybersecurity Working Group recently urged organizations across sectors to begin migrating, warning that the transition will take time. Dos Santos says government expectations often converge on 2030, a year when experts expect quantum computers might be able to break existing encryption. For data that must stay confidential for many years, HNDL makes waiting for that milestone a poor fit.

Match the protection to the device and the data

Not every device transfer carries the same risk. Healthcare information, financial records, trade secrets, software code, and industrial designs can remain sensitive well after they are sent. Other information may lose sensitivity sooner, and devices differ in their computing power, memory, and network capacity. Security teams need to account for those differences when setting priorities.

Sharon Hagi, chief security officer at IoT security firm Finite State, has argued for a risk assessment that considers data lifetime, how quickly its sensitivity declines, device type, computing limits, and realistic timelines for adversaries. She also points to distinctions among cryptographic algorithms. Shor’s algorithm threatens RSA and elliptic-curve cryptography, while it does not make AES-256 or SHA-3 practically breakable. Grover’s algorithm offers at most a quadratic speedup, and properly sized symmetric algorithms retain useful security margins for many applications.

For constrained embedded devices, Hagi says, symmetric encryption paired with keys distributed out of band or provisioned in advance may remain a viable design. NIST PQC algorithms such as ML-KEM and ML-DSA can impose meaningful demands on processing, bandwidth, and memory. Device manufacturers will need to determine where those costs are manageable.

Where a direct upgrade is impractical, operators can use a gateway to protect traffic crossing a boundary. For example, a hospital could route image transfers to an external radiology provider through a gateway that supports quantum-resistant protocols. The link between the scanner or image archive and that gateway still needs protection; network segmentation and removing direct internet access may reduce exposure on that part of the path.

Such a gateway only protects the connection if both endpoints can negotiate a compatible algorithm. Interoperability is already a concern: a September Thales Manufacturing Data Threat Report, based on 417 respondents in 20 countries, found that 30% were behind on their post-quantum interoperability objectives.

Build an inventory that connects devices to data

Dos Santos recommends that operators inventory devices, data, and communications together. A useful map shows which transfers already have compatible protection, which depend on a firmware or software update, and where a gateway could secure an external connection. It can also reveal which systems hold data with a long confidentiality lifetime, helping teams prioritize effort.

For healthcare, Forescout recommends starting with patient portals, external APIs, partner exchanges, and other internet-facing links. Teams can then update cryptographic libraries and firmware where feasible, seek vendor migration plans, and assess gateway and isolation options for equipment that cannot be upgraded. If a manufacturer has no viable migration path, replacement may need to enter the plan.

Operators should ask vendors when PQC communications support will arrive, which connections it will cover, and whether new hardware will be needed. Those answers can inform purchasing and support agreements for devices expected to remain in service for years. The G7 call encourages organizations to fold quantum-safe replacements into normal equipment refreshes. US Office of Management and Budget guidance from June similarly directs federal agencies to include PQC upgrades in hardware refreshes and prioritize equipment that cannot support PQC or hybrid cryptography for replacement or decommissioning.

The immediate task is to make the device and data paths visible. That inventory gives security teams a basis for protecting exposed connections now, planning upgrades with manufacturers, and identifying equipment that needs a gateway or eventual replacement.