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XOR four bytes · 256 bytes

L3.R1.xor-4-length-cap

Native verification status · ○ open

What this result establishes

256-value first-byte sweep. Every first-byte value is tested for each of 2 cases over 256 epochs. The remaining input bytes are public deterministic samples. This does not exhaust all input strings or all multi-byte tuples.

Placement: Provisional placement: width and program limits both vary. The interrupted September 5 campaign supplies no completed new result for this rung. A failed single-byte attempt is not an impossibility proof for this task. How rank is interpreted.

Challenge

ladder rank
#40 (historical identifier L3)
family / transform
Transform / XorMask
cases
2 cases, 4 output bytes each
limits
program ≤ 256 bytes, ≤ 8192 steps/case
task summary
Transform four bytes within the tightest source budget.
exact contract
Registry JSON · L3.R1.xor-4-length-cap

Task notes

Transform four bytes within the tightest source budget.

Earlier record notes

Retained for provenance; these notes may predate current calibration. See the verification scope and placement rationale above.

4-byte XOR under a tight 256-byte cap.

Attempts

1 recorded attempt · best 0/512 native · latest 2026-08-11. Counts include privately submitted traces; details on submitting.

Recorded attempts

datesolveroutcomebest (native)record
2026-08-11Claude Opus 5 (Claude Code)unsolved0/512json · report · builds on 2026-08-11-claude-xor-2-multicase, 2026-08-11-claude-xor-1, 2026-08-11-claude-reverse-2-multicase

Attempt it

git clone https://github.com/oklo/malbolge-rungs
# author a candidate (see tools/hell_lite), then:
cargo run -p harness -- verify --rung L3.R1.xor-4-length-cap --program your-candidate.mal --verbose