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    Code Signing

    Cryptographic signing of executable software and firmware so that only authentic, unmodified code from a trusted publisher will run.

    Reviewed by Christian Espinosa, Founder, Blue Goat CyberLast reviewed June 20, 2026

    Definition

    Code signing is the practice of digitally signing executable files, firmware images, software packages, and OTA updates with a private key whose corresponding public key (in a certificate from a trusted certificate authority) is embedded in or trusted by the device. At install or boot, the device verifies the signature; if it doesn't validate against an expected publisher and the artifact hasn't been modified, the code is rejected. Code signing is the foundational control behind secure boot, OTA update verification, and anti-tampering on connected medical devices.
    What the regulation says
    FDA's 2023 Cybersecurity in Medical Devices guidance lists 'Authenticity and Integrity of Updates' as a core security capability. IEC 81001-5-1 §5.7.2 and §9.6 expect signed updates and secure key management. AAMI SW96 requires code signing for distributed software components.

    What this means in practice

    FDA premarket cybersecurity submissions are expected to describe how the device verifies the authenticity and integrity of firmware and software updates. Code signing, paired with a hardware root of trust to protect verification keys, is the standard answer. Key management is where most code-signing programs fail: signing keys stored in source control, in unprotected CI build agents, or shared across product lines have caused some of the most severe medical device cybersecurity advisories.
    Common pitfalls
    • •Storing signing keys in CI/CD environment variables or unencrypted on build servers, keys belong in an HSM or hardware-backed key store.
    • •Using the same signing key across product lines and over many years, key rotation and per-product or per-release keys limit blast radius.
    • •Verifying signatures only at install time, not at boot, pair code signing with secure boot to defend against post-install tampering.
    Grouped by theme

    Primary references

    3 sources
    Link health: 3 verified· last checked 2026-06-20
    FDA·1NIST·1MDCG·1
    1. 1
      FDA Cybersecurity in Medical Devices guidance (2023)
      Verified
      FDAfda.gov
    2. 2
      NIST SP 800-57: Key Management
      Verified
      NISTcsrc.nist.gov
    3. 3
      MDCG Cybersecurity Guidance
      Verified
      MDCGhealth.ec.europa.eu

    Inline markers like [1] jump to the matching reference above.