ISO/IEC 11770-6:2016 PDF

Overview

ISO/IEC 11770-6:2016 - "Information technology - Security techniques - Key management - Part 6: Key derivation" specifies standardized key derivation functions (KDFs) that produce one or more secret keys from existing secret input plus public parameters. The standard defines both MAC‑based and hash‑based KDF constructions, and describes models, notation, and relationships to the key management life cycle. It is part of the ISO/IEC 11770 key management series.

Key topics and requirements

• One‑step vs Two‑step KDFs
  • One‑step KDFs (OKDF1…OKDF6): transform secret input directly into key(s) in a single operation - typically used when the input is already a secret key or the function is used only once.
  • Two‑step KDFs: separate key extraction (e.g., KTF1) and key expansion (KPF1…KPF4) phases. The extraction produces a MAC key; expansion generates application keys (examples: TKDF1…TKDF4).
• Cryptographic primitives
  • KDFs defined using Message Authentication Codes (MACs) and hash functions. Normative references include ISO/IEC 9797 (MACs) and ISO/IEC 10118 (hash‑functions).
• Security considerations
  • Treatment of entropy, confidentiality of derived keys, use of non‑secret parameters (labels, context), and safe reuse rules.
  • Guidance on choosing one‑step vs two‑step based on input entropy and reuse.
• Structure and guidance
  • Formal notation, object identifiers (Annex A), and informative guidance for correct use (Annex B).

Applications

ISO/IEC 11770-6 provides practical, interoperable KDF specifications for:

• Deriving encryption and MAC keys from pre‑existing secrets (passwords, master keys, shared secrets)
• Generating multiple purpose keys (separation of keys for encryption, authentication, session handling)
• Improving entropy/uniformity of non‑ideal secret material via extraction
• Key management in constrained devices, secure storage, and secure communications where standardized KDFs are required

Who should use this standard

• Cryptographic library implementers and protocol designers
• Security architects and engineers designing key management schemes
• Certification and compliance teams validating KDF usage
• Vendors of secure hardware, IoT devices, and enterprise security products

Related standards

• ISO/IEC 11770 (series) - Key management
• ISO/IEC 9797 - Message Authentication Codes (MACs)
• ISO/IEC 10118 - Hash‑functions
• ISO/IEC 11770‑1 - Key management terms and concepts

Using ISO/IEC 11770-6:2016 helps ensure secure, interoperable key derivation practices by specifying vetted MAC‑ and hash‑based KDF constructions and clear guidance for practical deployment.