Overview
ISO/IEC 11770-4:2017 - "Information technology - Security techniques - Key management - Part 4: Mechanisms based on weak secrets" specifies cryptographic mechanisms for establishing secret keys when the starting secret is a human-memorizable, weak secret (e.g., a password). The standard defines techniques that enable password‑based key agreement and key retrieval while preventing offline brute‑force and dictionary attacks on those weak secrets. It does not cover life‑cycle management or storage/archival/destruction of secrets and keys.
Key topics and technical requirements
- Definition of weak secrets: secrets chosen from a relatively small set (memorized passwords) and the associated attack model (brute‑force and dictionary attacks).
- Password‑authenticated key agreement (PAKE): balanced and augmented schemes to negotiate shared keys securely.
- Balanced mechanisms (BKAM1, BKAM2) - for two parties that share the same weak secret.
- Augmented mechanisms (AKAM1, AKAM2, AKAM3) - for client/server scenarios where the server stores verification data derived from the client’s weak secret (one‑way verifier).
- BKAM2 is based on J-PAKE; AKAM3 is based on AugPAKE (reflected in the standard).
- Password‑authenticated key retrieval (KRM1): protocols for a party to retrieve or reconstruct keys with server assistance using a weak secret.
- Domain parameters and cryptographic primitives: specification of required domain parameters, hash‑functions (collision‑resistant), finite field and elliptic curve considerations (references to ISO/IEC 10118‑1 and ISO/IEC 15946‑1 concepts appear).
- Functional building blocks and operations: prior shared parameters, functions for data conversion (Annex A), object identifiers (Annex B), and guidance on parameter choices (Annex C).
- Security goals: guarantee that secret keys are established only when the correct weak secret/verifier is used, and to limit offline guessing feasibility.
Note: the document includes a patent notice and records known patent declarations.
Practical applications
- Secure password‑based authentication and session key establishment for:
- Client–server systems (web, API, authentication servers)
- Mobile and desktop applications requiring password-derived keys
- Environments where clients cannot store strong secrets securely and need server‑assisted retrieval
- Use cases that require resistance to offline password‑guessing attacks while relying on memorized credentials.
Who should use this standard
- Security architects and protocol designers specifying password‑based key agreement or retrieval.
- Software/security engineers implementing PAKE/AugPAKE/J‑PAKE derived protocols.
- Vendors of authentication servers, identity platforms, and secure storage solutions.
- Auditors and compliance officers assessing password‑based key management controls.
Related standards
Keywords: ISO/IEC 11770-4:2017, weak secrets, password-authenticated key agreement, PAKE, J-PAKE, AugPAKE, key retrieval, offline brute-force protection.
Open preview (PDF)Information technology — Security techniques — Key management — Part 4: Mechanisms based on weak secrets