Digital signature schemes play a vital role in ensuring secure communication, authentication, and data integrity across numerous applications, including secure email, financial transactions, and blockchain systems. However, classical schemes like RSA and ECDSA are vulnerable to quantum attacks, prompting a global shift toward post-quantum cryptographic alternatives. As part of this transition, NIST has already standardized three post-quantum cryptographic schemes: (i) ML-KEM (FIPS 203) for key encapsulation, based on CRYSTALS-Kyber; (ii) ML-DSA (FIPS 204) for digital signatures, derived from CRYSTALS-Dilithium; and (iii) SLH-DSA (FIPS 205), a stateless hash-based signature scheme based on $\rm SPHINCS^+$. Hash-based digital signature schemes are particularly important because their security is based on the properties of cryptographic hash functions, rather than number-theoretic problems, offering a more robust foundation for post-quantum security.
An important type of digital signature schemes is Group Signature Schemes which enable members of a group to sign messages anonymously on behalf of the group while a designated authority is able to reveal the signer’s identity when necessary hence it ensures accountability. Such functionality is critical in privacy-preserving applications like direct anonymous attestations and reputation systems. Fully dynamic GSSs are especially valuable as they allow users to join or be revoked without requiring system-wide updates—an essential property for real-world scenarios.
In this talk, after introducing digital signatures and their everyday applications, I will review several hash-based group signature scheme proposals, including G-Merkle, DGM, DGMT, and SPHINX-in-the-Head, highlighting their limitations in terms of scalability and efficiency. I will then present DGSP, our newly proposed scalable and efficient fully dynamic group signature scheme, and compare it with existing post-quantum alternatives to demonstrate its advantages.
Zoom room information:
https://us06web.zoom.us/j/84906984159?pwd=BCWaIbXBuku3A5I84zNg9mHFxVZjXD.1
Meeting ID: 849 0698 4159
Passcode: 362880