ISO/IEC 14888-2:2008

Overview

ISO/IEC 14888-2:2008 defines digital signatures with appendix whose security is based on the difficulty of integer factorization. It is Part 2 of the ISO/IEC 14888 series and specifies the mathematical relationships, signature generation mechanisms, and verification procedures for a family of factorization-based signature schemes. The standard covers both certificate-based and identity-based mechanisms (including RSA, RW, ESIGN, GQ1 and newer GQ2, GPS1, GPS2 schemes) and includes use of the PSS format mechanism where applicable.

Key topics and technical requirements

• Signature model: Digital signatures with appendix - the signature does not recover any part of the message; the signed message = signature + full message.
• Security basis: All schemes depend on the infeasibility of factoring the modulus (n).
• Data element constraints: Specifies required relationships and constraints among domain parameters, private signature keys, and public verification keys.
• Operations defined:
  • Key pair generation (requires random bits and prime generation - note: RNG/prime generation methods are out of scope).
  • Signature production (deterministic or probabilistic depending on scheme and use of salt).
  • Signature verification (deterministic).
• Included schemes:
  • Certificate-based: RSA, RW, ESIGN (with corrigendum addressed).
  • Identity-based and certificate-based variants: GQ1, GQ2, GPS1, GPS2.
  • PSS format mechanism and guidance on using it with RSA, RW, GQ1, ESIGN.
• Auxiliary elements: Object identifiers for schemes/options; annexes with parameter guidance, numerical examples, format mechanisms and interoperability notes.
• Out-of-scope: Random-bit/prime generation techniques and certificate/key management procedures (referenced to ISO/IEC 18031, 18032 and PKI standards).

Applications and intended users

• Implementers building cryptographic libraries and secure applications that require factorization-based digital signatures.
• Security architects and PKI designers selecting signature algorithms (RSA, ESIGN, GN/ GPS schemes) for authentication, non-repudiation and data integrity.
• Compliance officers and auditors verifying conformance to international cryptographic standards.
• Cryptographers and protocol designers referencing standardized mechanisms, PSS formatting, and object identifiers for interoperability.
• Manufacturers of secure signature devices (smart cards, HSMs) ensuring proper parameter constraints and verification behavior.

Related standards

• ISO/IEC 14888-1 (General - digital signatures with appendix)
• ISO/IEC 14888-3 (Discrete logarithm based mechanisms / Part 3)
• ISO/IEC 9796 (signatures with message recovery) - contrasted with appendix-style signatures
• ISO/IEC 10118 (Hash-functions), ISO/IEC 18031/18032 (randomness guidance)

ISO/IEC 14888-2:2008 is essential reading for anyone implementing or specifying factorization-based digital signature systems and seeking standardized, interoperable mechanisms for secure signature generation and verification.