MuseAir algorithm v2 (crate 0.6.0)

This is a separate package and score from MuseAir v0.3. The selected 32-byte pair has L = 4 and an upstream-confirmed rate 36,060/(1.5·2^32) = 2^-17.447, yielding a sampled cap 19.45 bits (95% interval 19.43–19.46).

M  = 0000000000000000000000000000000000000000000000000000000000000000
M' = 00000000000000404a048402a910048a00000000000000a80000000000000000
key words = 040963434fe5e368
output = ef46cda19c0bbc67

Seed 0 does not collide. The scored key model is one uniform 64-bit seed for museair::hash. bfast::hash collides on the same seeds. The two 128-bit functions use two independent uniform seeds and have the same measured rate on a different event set.

For 17–32 bytes the tail enters as wmul(C4 ^ seed ^ u, C5). Flipping tail bits 59/61/63 changes the product by ±21·C5; the product’s XOR image matches a fixed head difference when the multiplication carries agree. The selected head XORs are 0x4000000000000000 and 0x8a0410a90284044a. This bounded-search witness is not a proof that no better pair exists.

cc -O3 -std=c11 museair_v2_verify.c -lm -pthread -o check
taskset -c 24-31 nice -n 10 ./check 24
# The literal-message sampler and at-seed helper are also supplied:
cc -O3 -std=c11 measure.c -lm -pthread -o measure
cc -O3 -std=c11 at_seed.c -o at_seed
cd native
cargo build --release --locked
taskset -c 24-31 nice -n 10 ./target/release/museair_v2_verify 0000000000000000000000000000000000000000000000000000000000000000 00000000000000404a048402a910048a00000000000000a80000000000000000 26 79 8 040963434fe5e368 0

The standalone C program uses the independently cross-checked port in museair2.h and asserts the selected collision and seed-0 noncollision before sampling. Default 24 1 uses one SplitMix64 stream. The Xeon observed 84, 84, 81, 81 / 2^24 for hash, bfast::hash, hash128, bfast::hash128 respectively (log); 20 1 gives 3 3 0 0 (log).

The native Rust program links directly to pinned crates.io museair = 0.6.0, with Cargo.lock supplied. Its independent xoshiro256** streams at 26 79 8 gave 388, 388, 387, 387 / 2^26, and reproduced both the example and seed-0 noncollision (native log). The example output is ef46cda19c0bbc67 (bfast: 8d303f6a6db80174). The smaller package checks do not replace the large confirmation samples.

Search and C-port validation; independent upstream verifier. The supplied C port is MIT; upstream crate 0.6.0 is MIT OR Apache-2.0 (per its Cargo.toml); preserve upstream license notices when redistributing the crate. The historical v0.3 every-seed witness does not transfer to v2 (0/2^24). No v0.3 timing is reused for v2.

All page-pass executions were run on the Xeon on 2026-09-19 with taskset -c 24-31 nice -n 10. These small reruns validate the package and deterministic counts; the larger independently reproduced records linked below supply the published estimates. Messages are fixed before the key is sampled.