Security strength

When FDA guidance asks for strong cryptography, it refers to this measure. Choosing current, recognized algorithms and key lengths is how manufacturers show adequate security strength.

a measure of the computational complexity associated with recovering certain secret and/or security-critical information concerning a given cryptographic algorithm from known data (e.g., plaintext/ciphertext pairs for a given encryption algorithm). Throughout this guidance “strong” and other iterations of this term may be used that apply to this definition.

FDA guidance: Cybersecurity in Medical Devices: Quality Management System Considerations and Content of Premarket Submissions (February 2026), Appendix 5, Terminology