The Round 3 candidates were announced May 14, 2026. NIST IR 8610, Status Report on the Second Round of the Additional Digital Signature Schemes for the NIST Post-Quantum Cryptography Standardization Process is now available.
Background
NIST initiated the public Post-Quantum Cryptography (PQC) Standardization Process in December 2016 to select quantum-resistant public-key cryptographic algorithms for standardization in response to the substantial development and advancement of quantum computing. After three rounds of evaluation and analysis, NIST announced the selection of the first algorithms to be standardized. The public-key encapsulation mechanism (KEM) selected for standardization was CRYSTALS-KYBER (ML-KEM). The digital signatures selected were CRYSTALS-Dilithium (ML-DSA), FALCON (FN-DSA), and SPHINCS+ (SLH-DSA). Except for SPHINCS+, all of these schemes are based on the computational hardness of problems that involve structured lattices. While several non-lattice-based KEMs remained under consideration in the fourth round, no signature schemes remained.
In September 2022, NIST called for additional digital signature proposals to be considered in the PQC standardization process to diversify its post-quantum signature portfolio. Since two signature schemes based on structured lattices had already been standardized, NIST expressed particular interest in additional general-purpose signature schemes based on a security assumption that did not use structured lattices as well as signature schemes with short signatures and fast verification. The call for submissions closed June 1, 2023, with 40 algorithms being evaluated in the first round. After almost a year and a half, fourteen second-round candidates were announced. The second round continued until May 2026.
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