--- title: "Side-Channel Attack, Definition | MedTech Terms" description: "An attack that extracts secrets by analyzing physical or timing signals rather than breaking cryptography directly." lang: en json-ld: | { "@context": "https://schema.org", "@graph": [ { "@type": "DefinedTerm", "@id": "https://medtechterms.com/terms/side-channel#term", "name": "Side-Channel Attack", "description": "A side-channel attack extracts secret data - typically cryptographic keys, PINs, or biometric templates - by measuring physical phenomena that leak from a device while it processes those secrets, rather than by breaking the cryptographic algorithm itself. Common side channels include power consumption (DPA - Differential Power Analysis), electromagnetic emissions (TEMPEST/EM-SCA), execution timing, cache access patterns, and acoustic emissions. 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It requires specialized equipment (oscilloscopes, EM probes) and is usually scoped separately for high-risk devices." } }, { "@type": "Question", "name": "Does TLS protect against side channels?", "acceptedAnswer": { "@type": "Answer", "text": "TLS protects data in transit but the device's local key storage and crypto operations remain side-channel-exposed. The transport-layer protection is irrelevant if the attacker can extract the key from the device." } }, { "@type": "Question", "name": "Are side-channel attacks realistic against medical devices?", "acceptedAnswer": { "@type": "Answer", "text": "For implantable cardiac devices and insulin pumps, several published academic attacks have demonstrated practical key extraction. Threat models should treat them as plausible for any device an adversary can physically access." } } ] } ] } --- [ MedTech Terms The authoritative reference ](/) Browse Learn [Latest](/latest) About 1. [Home](/) 2. / 3. [Terms](/terms) 4. / 5. [Cybersecurity](/terms?cat=Cybersecurity) 6. / 7. Side-Channel Attack [All terms](/terms) Cybersecurity [Connected & Cyber-Physical Devices](/ecosystems/connected-devices) # Side-Channel Attack An attack that extracts secrets by analyzing physical or timing signals rather than breaking cryptography directly. Reviewed by [Christian Espinosa, Founder, Blue Goat Cyber](/authors/christian-espinosa) Last reviewed May 5, 2026 ## Definition A side-channel attack extracts secret data - typically cryptographic keys, PINs, or biometric templates - by measuring physical phenomena that leak from a device while it processes those secrets, rather than by breaking the cryptographic algorithm itself. Common side channels include power consumption (DPA - Differential Power Analysis), electromagnetic emissions (TEMPEST/EM-SCA), execution timing, cache access patterns, and acoustic emissions. The 2018 Meltdown/Spectre family demonstrated the relevance of cache-timing side channels even on commodity CPUs. What the regulation says FDA's 2023 guidance does not call side-channel attacks out by name but expects threat models to consider physical-access scenarios for devices that store credentials or keys locally. NIST SP 800-90B covers entropy considerations relevant to side-channel exposure of RNGs. For high-assurance devices (implantables, devices handling biometric authentication), side-channel resistance should be addressed in design. ## What this means in practice Side-channel resistance matters most for devices an attacker can physically possess (implantable programmers, home-use devices) and for any device where extracting a single device's keys would compromise an entire fleet. Commodity hardware typically lacks side-channel hardening; secure elements and dedicated crypto coprocessors include countermeasures. Common pitfalls - • Storing per-device keys in commodity microcontroller flash with no side-channel hardening. - • Implementing cryptography in software with non-constant-time operations. - • Re-using a single signing key across an entire device fleet - one extraction compromises all. ## Frequently asked questions Is side-channel testing part of pen testing? Standard pen testing typically does not include side-channel analysis. It requires specialized equipment (oscilloscopes, EM probes) and is usually scoped separately for high-risk devices. Does TLS protect against side channels? Are side-channel attacks realistic against medical devices? ## Related terms Grouped by theme ### Editor's picks · Hand-selected related concepts [ Cybersecurity Hardcoded Credentials Secrets - passwords, API keys, certificates - embedded in firmware or source code shipped on every device. ](/terms/hardcoded-credentials)[ Cybersecurity Premarket Cybersecurity Submission The bundle of cybersecurity artifacts a sponsor includes in a 510(k), De Novo, PMA, or HDE submission for a cyber device. ](/terms/premarket-cybersecurity)[ Cybersecurity Secure Boot A chain-of-trust mechanism that ensures only cryptographically signed firmware and software can run on a device. ](/terms/secure-boot)[ Cybersecurity Threat Modeling A structured analysis that identifies how an attacker could compromise a medical device and what controls mitigate each threat. ](/terms/threat-modeling) ### More in Cybersecurity · Same category [ Cybersecurity AAMI SW96 AAMI/ANSI standard establishing requirements for medical-device cybersecurity activities throughout the lifecycle. ](/terms/aami-sw96)[ Cybersecurity AAMI TIR57 AAMI Technical Information Report providing MedTech-specific guidance on cybersecurity risk management. ](/terms/aami-tir57)[ Cybersecurity AAMI TIR97(TIR97) AAMI Technical Information Report on post-market security risk management for medical device manufacturers, the operational companion to TIR57. ](/terms/aami-tir97)[ Cybersecurity Brainjacking Unauthorized remote control of an implanted neurostimulator (e.g., DBS) to alter stimulation parameters and harm a patient. ](/terms/brainjacking) Cited by Where this term appears across MedTech Terms. Ecosystems (1) - [Connected & Cyber-Physical Devices](/ecosystems/connected-devices) ## Primary references 3 sources Link health: 3 verified · last checked 2026-06-20 NIST· 1 FDA· 1 MDCG· 1 1. [1 NIST SP 800-90B Recommendation for the Entropy Sources Verified NIST · csrc.nist.gov ](https://csrc.nist.gov/publications/detail/sp/800-90b/final) 2. [2 FDA Cybersecurity Guidance (Sept 2023) Verified FDA · fda.gov ](https://www.fda.gov/regulatory-information/search-fda-guidance-documents/cybersecurity-medical-devices-quality-system-considerations-and-content-premarket-submissions) 3. [3 MDCG Cybersecurity Guidance Verified MDCG · health.ec.europa.eu ](https://health.ec.europa.eu/medical-devices-sector/new-regulations/guidance-mdcg-endorsed-documents-and-other-guidance_en) Inline markers like \[1\] jump to the matching reference above. Sponsor note ### Working on medical device cybersecurity? Blue Goat Cyber specializes in MedTech cybersecurity - threat modeling, SBOMs, penetration testing, and FDA premarket submissions. [Book a 30-minute discovery session](https://go.bluegoatcyber.com/meetings/blue-goat-cyber/discovery-session) - No obligation - Expert-led from minute one - NDA available on request MedTech Terms is a community resource sponsored by [Blue Goat Cyber](https://bluegoatcyber.com). Definitions are independent of any vendor. On this term Category Cybersecurity Sources 3 Updated 5/5/2026 [Compare with another term](/compare?a=side-channel) Learn in 60 seconds Card Lesson Quiz An attack that extracts secrets by analyzing physical or timing signals rather than breaking cryptography directly. - · Commodity hardware typically lacks side-channel hardening; secure elements and dedicated crypto coprocessors include countermeasures. - · Common side channels include power consumption (DPA - Differential Power Analysis), electromagnetic emissions (TEMPEST/EM-SCA), execution timing, cache access patterns, and acoustic emissions. - · The 2018 Meltdown/Spectre family demonstrated the relevance of cache-timing side channels even on commodity CPUs. Remember this Watch out: Storing per-device keys in commodity microcontroller flash with no side-channel hardening. Related terms - [Secure Boot ](/terms/secure-boot) - [Threat Modeling ](/terms/threat-modeling) - [Premarket Cybersecurity Submission ](/terms/premarket-cybersecurity) - [Hardcoded Credentials ](/terms/hardcoded-credentials) You may also need Auto-suggested from Cybersecurity and shared keywords. - [Hardware Root of Trust(HRoT) ](/terms/hardware-root-of-trust) - [MITRE ATT&CK(ATT&CK) ](/terms/mitre-attack) - [Software Bill of Materials(SBOM) ](/terms/sbom) - [Cryptographic Agility ](/terms/crypto-agility) - [Device Master File(MAF) ](/terms/device-master-file) - [Electronic Data Capture(EDC) ](/terms/edc) [All Cybersecurity terms](/terms?cat=Cybersecurity) From the Blue Goat network Related resources and services on this topic. - [ MedTech Cybersecurity Standards Authoritative reference for the standards and guidances behind medical device cybersecurity. ](https://medtechcyberstandards.com) - [ MedTech Cyber Tips Practical, organized tips for medical device cybersecurity teams. ](https://medtechcybertips.com) - [ MedTech Cybersecurity Crosswalk International crosswalk of medical device cybersecurity requirements across regulators. ](https://mdccrosswalk.com) - [ Code Blue Real medical device cybersecurity incidents and their lessons. ](https://codebluechart.com) MedTech Terms An authoritative, plain-language reference for the regulatory, quality, cybersecurity, and software terms that shape modern medical devices. 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