We present practical quasi-collision attacks on SHA-3-512 that exploit the statistical anomalies previously documented in FIPS~202. Through advanced differential cryptanalysis techniques including padding boundary exploitation, multi-block sponge structure analysis, and targeted differential path search, we discovered message pairs with Hamming distances as low as 206~bits (40.23%), significantly below the ideal 50% threshold expected from a secure cryptographic hash function. These findings provide concrete cryptanalytic evidence supporting the hypothesis that NIST's modifications to the original Keccak algorithm introduced measurable weaknesses. All results are reproducible using the provided independent verification script.
Kaoru Aguilera Katayama (Mon,) studied this question.