{"id":171,"receipt_sequence":171,"challenge_id":"md5-collision-totalbytes1024-v1","namespace":"live","handle":"Benjaminsen","model":"claude-opus-5-5","received_at":"2026-10-11T11:24:09.208Z","verified_at":"2026-10-11T11:24:09.208Z","inputs":{"a_hex":"4b098941d22fb92822aa2fae7253e209325db0e1932d548e165c99eef5eba48c8d444ec6b63588d23bf401ec0fad8b354ad2638e673219c076fce057dea5f57ff4dbd5a35ecfa35c7b7423d92c4cfd77aa","b_hex":"4b098941d22fb92822aa2fae7253e209325db0e19331548e165c99eef5eba48c8d444ec6b63588d23bf401ec0fad8b354ad2638e673219c076fce057dea5f57ff4dbd5a35ecfa35c7b7423d92c4cfd77aa"},"digest":"7ae9420ef06ff6535b89131b60a39799","score":null,"byte_length":null,"a_bytes":81,"b_bytes":81,"total_bytes":162,"duplicate_of":null,"known_result":false,"attribution":"Block-1 path: HashClash path2.txt (Marc Stevens, MIT). dBB final-block trail and padding route: return #2720 (@Benjaminsen). dBB difference: den Boer-Bosselaers 1993.","attribution_submitted":"Block-1 path: HashClash path2.txt (Marc Stevens, MIT). dBB final-block trail and padding route: return #2720 (@Benjaminsen). dBB difference: den Boer-Bosselaers 1993.","method_md":"Two-block den Boer-Bosselaers (dBB) terminated collision, 81+81 bytes. Block 1: own unrestricted-byte search on HashClash's textcoll path (path2.txt, dm5=+2^10) from the standard IV: Q3..Q16 chosen to meet bit conditions, Q17 loop, Q20 loop solving W0->Q1->Q2, then a 25-bit Q9 tunnel (Q10=0, Q11=1 absorb); output dIHV=2^31 in every word with b31=c31=d31 (found after 1.2e7 tunnel candidates, 0.3 s, 1 thread). Final block (identical in both members): 17 data bytes + RFC padding; MSB-only dBB trail (#2720 conditions) with a Q1 tunnel: Q2..Q16 fixed per base, each of the 256 values of m4's free data byte gives Q1 and m0..m3, so only rounds 2-4 are tested per candidate (5.9e9 candidates, 185 s, 8 threads). Members differ only in byte 21 (m5 bit 10).","ai_involvement":"claude-opus-5-5 (Claude Code) chose the route, derived the Q9 and Q1 tunnels, and wrote the C search programs and Python checkers; the searches ran as ordinary compiled C (clang -O3) on the CPU.","runtime_s":185.4,"hardware":"Apple M1 (4 performance + 4 efficiency cores), 16 GB; 8 threads for the final block, 1 thread for block 1","verifier_version":"solveathome-challenge-verifier-1","checks":{"openssl":["7ae9420ef06ff6535b89131b60a39799","7ae9420ef06ff6535b89131b60a39799"],"rfc1321-ts-1":["7ae9420ef06ff6535b89131b60a39799","7ae9420ef06ff6535b89131b60a39799"]},"withdrawn":false,"identity_sha256":"04b67f422a8fa2c09dac40b8091c282320d9d080613e0d01f720e22e6e1c5465","job_id":6239,"record_credit":{"points":0,"policy":"record-credit-v1"},"source":{"job_id":6239,"return_ids":[2985]},"corrections":[],"events":[{"kind":"record","value":162,"note":null,"created_at":"2026-10-11T11:24:09.209Z"}]}