Extend mlkem_top with a runtime op_i select (0=KeyGen, 1=Encaps) and the
first Encaps stages, reusing the shared keccak_core and the ST_H multi-block
SHA3-256 machinery:
ST_ENC_H: H(ek) over preloaded ek_bram (same FSM as KeyGen ST_H)
ST_ENC_G: (K,r) = G(m||H(ek)) via new 64-byte single-block SHA3-512
- sha3_top_shared: add mode=2'b11 = SHA3-512 over a full 512-bit message
(g512_pad). Standalone tb_sha3_g512 confirms it byte-exact.
- mlkem_top: new ports op_i, msg_i, ek_in_{we,addr,byte} (ek preload), ss_o,
dbg_ct_*, dbg_r_o/dbg_hek_o. st widened 4->5 bits; ST_ENC_* states added.
Renamed message port to msg_i to avoid collision with ST_M counter m_i.
- TB tb_mlkem_enc_katK + gen_encaps_vectors.py (per-byte ek/m/ct/ss vectors).
Verified ss==KAT.ss for K=2/3/4, cases 0-2 (all PASS). KeyGen unaffected
(K=2 c0 still ek==pk, dk==sk byte-exact).
sample_ntt was non-conformant: both RTL and the test reference re-ran
keccak_p after every 3-byte squeeze instead of consuming the full
1344-bit SHAKE-128 rate. Only coeff[0] matched a standard sampler, so
the generated A matrix would not interoperate with any compliant ML-KEM.
- sample_ntt_sync{,_shared}.v: walk all 56 groups of the rate block via
grp_ptr_r; re-permute only when the block is exhausted. Verified
256/256 against ml-kem-r Rust sample_ntt on two seeds, and 1536/1536
in the Verilator framework (runtime ~128x faster per poly).
- gen_vectors.py: use a self-contained hashlib.shake_128 oracle.
sha3 testbench fixes (all now self-check hash_o against verified vectors,
cross-checked with hashlib and ml-kem-r mlkem_G):
- tb_sha3_xsim_simple.v: test G/H/J modes, not just G.
- tb_keccak_core_xsim.v: correct the wrong EXPECTED_STATE constant
(RTL was correct; lane0 = 0xf1258f7940e1dde7 per FIPS 202).
- tb_sha3_xsim.v: read expected file and self-check per vector; add
vectors/g_basic_{input,expected}.hex (3 G / 2 H / 2 J).
Remove stale sha3_chain test (its RTL was deleted in 1cace51) and its
README references. Extend .gitignore for XSIM artifacts and result dumps.
