Twin-Schnorr: a security upgrade for the Schnorr identity-based identification scheme

Area of Science:

• Cryptography
• Computer Science
• Information Security

Background:

• Most identity-based identification (IBI) schemes rely on pairing operations, which are computationally expensive and reduce efficiency.
• Existing IBI schemes often use interactive assumptions (e.g., one-more RSA inversion) for active/concurrent attack security, offering weaker guarantees.
• The Schnorr-IBI scheme is efficient and secure against passive attacks but struggles with active/concurrent attacks due to repeated protocols.

Purpose of the Study:

• To upgrade the Schnorr-IBI scheme to achieve security against active and concurrent impersonation attacks.
• To enhance security guarantees by utilizing the classical discrete logarithm assumption.
• To maintain efficiency by avoiding pairing operations.

Main Methods:

• The study modifies the Schnorr-IBI scheme, a pairing-free cryptographic protocol.
• The enhanced scheme leverages the classical discrete logarithm assumption for security proofs.
• The approach focuses on improving security against active and concurrent impersonation without relying on pairings.

Main Results:

• The upgraded Schnorr-IBI scheme provides security against active and concurrent impersonation attacks.
• The scheme relies solely on the classical discrete logarithm assumption, offering stronger security guarantees.
• The pairing-free design ensures continued efficiency, outperforming many pairing-based IBI schemes.

Conclusions:

• The enhanced Schnorr-IBI scheme offers a superior balance of security and efficiency for identity-based identification.
• This upgrade addresses the limitations of previous Schnorr-IBI schemes in handling active and concurrent attacks.
• The research presents a practical and secure IBI solution without the computational overhead of pairing operations.