Files
mlkem-sync/sync_rtl/top/mlkem_top.v
FallenSigh 851630f73c refactor(kg): merge G/H into single shared sha3_top (4->3 keccak_core)
ST_G (single-block G) and ST_H (multi-block H(ek)) are disjoint FSM phases,
so one sha3_top serves both: mb_en and ready_i are phase-muxed, h_hash/h_vo
alias the shared core's outputs. Removes the dedicated u_sha3_h instance and
its keccak_core. 11/11 KAT PASS (K=2 c0-4, K=3/4 c0-2), byte-exact, 0 file-not-found.
2026-06-28 15:23:30 +08:00

768 lines
33 KiB
Verilog

// mlkem_top.v - ML-KEM KeyGen top-level integration. Runtime-selectable
// parameter set via k_i: k=2 (ML-KEM-512, eta1=3), k=3 (768), k=4 (1024).
// Storage is sized for KMAX (worst case = ML-KEM-1024); k_i picks the
// active sub-range at start_i.
//
// Streaming valid/ready interface. Given seeds d and z, computes the
// ML-KEM key pair per FIPS 203 Algorithm 16 (KeyGen_internal):
// (rho,sigma) = G(d || K)
// A_hat[i][j] = SampleNTT(rho || j || i) i,j in 0..K-1
// s[i] = CBD3(PRF(sigma, i)), e[i] = CBD3(PRF(sigma, K+i))
// s_hat[i] = NTT(s[i]); e_hat[i] = NTT(e[i])
// t_hat[i] = e_hat[i] + sum_j A_hat[i][j] o s_hat[j]
// ek = byteEncode12(t_hat[0..K-1]) || rho
// dk = byteEncode12(s_hat[0..K-1]) || ek || H(ek) || z
//
// Built incrementally and verified stage-by-stage against ml-kem-r golden
// vectors (test_framework/modules/mlkem_keygen/golden) and NIST KAT.
//
// Uses independent (verified) leaf modules, each with its own keccak_core:
// sha3_top, sample_ntt_sync, sample_cbd_sync, ntt_core, poly_mul_sync,
// mod_add_sync. No shared-keccak arbiter.
`include "sync_rtl/common/defines.vh"
module mlkem_top #(
parameter KMAX = 4 // storage sizing (worst case = ML-KEM-1024)
) (
input clk,
input rst_n,
input [2:0] k_i, // RUNTIME ML-KEM param: 2=512, 3=768, 4=1024
input [255:0] d_i, // KeyGen seed d (byte 0 in d_i[7:0])
input [255:0] z_i, // implicit-rejection seed z
input start_i, // pulse to begin KeyGen
output busy_o, // high while running
output done_o, // pulse when ek/dk ready
// Debug readback tap: read one stored coefficient by (poly slot, index).
// Lets stage TBs verify intermediates without wide buses.
input [3:0] dbg_slot_i, // poly slot (see localparams below)
input [7:0] dbg_idx_i, // coefficient index 0..255
output [11:0] dbg_coeff_o,
// Debug byte readback: ek (sel=0, 0..799) / dk_pke (sel=1, 0..767)
input dbg_byte_sel_i,
input [10:0] dbg_byte_idx_i,
output [7:0] dbg_byte_o,
// Debug full-dk readback: dk = dk_pke(768) || ek(800) || H(ek)(32) || z(32)
// = 1632 bytes. Index 0..1631.
input [11:0] dbg_dk_idx_i,
output [7:0] dbg_dk_o,
// Debug taps for hash outputs
output [255:0] dbg_rho_o,
output [255:0] dbg_sigma_o
);
localparam Q = `Q; // 3329
// Runtime ML-KEM parameter, captured at start_i.
reg [2:0] k_r;
// FIPS 203: eta1 = 3 for ML-KEM-512 (k=2), else 2 (k=3/4).
wire [1:0] eta1_rt = (k_r == 3'd2) ? 2'd3 : 2'd2;
// Runtime-derived sizes (k_r in {2,3,4}). Small multiplies are cheap.
wire [5:0] kk_rt = k_r * k_r; // 4/9/16
wire [5:0] slot_s_rt = kk_rt; // s_hat base slot
wire [5:0] slot_e_rt = kk_rt + k_r; // e_hat base slot
wire [5:0] slot_t_rt = kk_rt + {1'b0, k_r} + {1'b0, k_r}; // t_hat base = kk+2k
wire [11:0] ek_bytes_rt = 12'd384 * {9'b0, k_r} + 12'd32; // 800/1184/1568
wire [11:0] dk_bytes_rt = 12'd384 * {9'b0, k_r}; // 768/1152/1536
// H(ek) block count = ceil((ek_bytes+1)/136): 6/9/12 for k=2/3/4 (table)
wire [3:0] h_nblk_rt = (k_r == 3'd2) ? 4'd6 : (k_r == 3'd3) ? 4'd9 : 4'd12;
wire [11:0] h_last_rt = {6'b0, h_nblk_rt} * 12'd136 - 12'd1; // final padded byte index
// ================================================================
// Polynomial storage, sized for KMAX (worst case). Runtime k uses a
// sub-range. Slot layout (each slot = 256 coeffs):
// A_hat[i][j] : slots 0 .. k*k-1 at index i*k + j
// s_hat[i] : slots slot_s_rt .. +k-1
// e_hat[i] : slots slot_e_rt .. +k-1
// t_hat[i] : slots slot_t_rt .. +k-1
// NUM_SLOTS = KMAX*KMAX + 3*KMAX = 28 for KMAX=4.
// ================================================================
localparam NUM_SLOTS = KMAX*KMAX + 3*KMAX;
localparam SAW = 5; // slot-address width (>=clog2(28))
reg [11:0] polymem [0:NUM_SLOTS*256-1];
// Debug readback (registered for timing)
reg [11:0] dbg_coeff_r;
always @(posedge clk) dbg_coeff_r <= polymem[dbg_slot_i*256 + dbg_idx_i];
assign dbg_coeff_o = dbg_coeff_r;
// ek and dk_pke byte memories sized for KMAX.
localparam EK_MAX = 384*KMAX + 32; // 1568
localparam DK_MAX = 384*KMAX; // 1536
// ek / dk_pke byte storage in BRAM (sd_bram: 1R/1W, 1-cycle read latency).
// Each single read port is shared time-disjointly: ST_H assemble reads ek
// (in ST_H), debug readback reads ek/dk (in ST_DONE). Write port driven by
// ST_E (1 byte/cycle) and the rho-tail copy.
wire [10:0] ek_rd_addr, dkp_rd_addr;
wire [7:0] ek_rd_data, dkp_rd_data;
reg ek_we, dkp_we;
reg [10:0] ek_wa, dkp_wa;
reg [7:0] ek_wd, dkp_wd;
sd_bram #(.W(8), .D(2048), .A(11)) u_ek_bram (
.clk(clk),
.rd_addr(ek_rd_addr), .rd_data(ek_rd_data),
.wr_en(ek_we), .wr_addr(ek_wa), .wr_data(ek_wd)
);
sd_bram #(.W(8), .D(2048), .A(11)) u_dkp_bram (
.clk(clk),
.rd_addr(dkp_rd_addr), .rd_data(dkp_rd_data),
.wr_en(dkp_we), .wr_addr(dkp_wa), .wr_data(dkp_wd)
);
// full dk = dk_pke(dk_bytes) || ek(ek_bytes) || H(ek)(32) || z(32)
wire [11:0] dk_ek_end = dk_bytes_rt + ek_bytes_rt; // ek region end
wire [11:0] dk_hek_end = dk_ek_end + 12'd32; // H(ek) region end
// Debug-region selects for dk readback (combinational region decode).
wire dbgdk_in_dkp = (dbg_dk_idx_i < dk_bytes_rt);
wire dbgdk_in_ek = (dbg_dk_idx_i >= dk_bytes_rt) && (dbg_dk_idx_i < dk_ek_end);
// Read-address muxes (declared here; depend on ST_H h_g defined below via
// the function-free expression h_blk*136 + h_byte). See assigns after the
// H-stage register declarations.
// dbg_byte_o / dbg_dk_o are combinational taps over the (registered) BRAM
// read data; net 1-cycle latency, well within the TB's 2-cycle read wait.
assign dbg_byte_o = dbg_byte_sel_i ? dkp_rd_data : ek_rd_data;
assign dbg_dk_o = dbgdk_in_dkp ? dkp_rd_data :
dbgdk_in_ek ? ek_rd_data :
(dbg_dk_idx_i < dk_hek_end) ? hek_r[(dbg_dk_idx_i - dk_ek_end)*8 +: 8]
: z_i[(dbg_dk_idx_i - dk_hek_end)*8 +: 8];
// ================================================================
// Top-level FSM (built incrementally). Stage 2a: G only.
// ================================================================
localparam ST_IDLE = 4'd0;
localparam ST_G = 4'd1; // run G(d||K), capture rho/sigma
localparam ST_A = 4'd2; // generate A_hat[i][j] via SampleNTT
localparam ST_C = 4'd3; // generate s[i],e[i] via CBD
localparam ST_N = 4'd4; // forward NTT of s[i],e[i] in place
localparam ST_M = 4'd5; // matrix accumulate t_hat = e_hat + sum A o s_hat
localparam ST_E = 4'd6; // byteEncode12 -> ek/dk BRAM
localparam ST_H = 4'd7; // H(ek) via multi-block SHA3-256
localparam ST_DONE = 4'd15;
reg [3:0] st, st_next;
reg [255:0] rho_r, sigma_r;
// A-generation bookkeeping: explicit i/j counters (avoid runtime divide)
reg [2:0] a_i; // row 0..k-1
reg [2:0] a_j; // col 0..k-1
reg [4:0] a_pair; // 0..k*k pairs done (for done test)
reg [7:0] a_widx; // write index 0..255 within current poly
reg a_busy; // 1 once current pair's request accepted (gates collect)
wire [SAW-1:0] a_slot = a_i*k_r + a_j; // A_hat[i][j] slot = i*k + j
// C-generation bookkeeping: 2*k polys (s[0..k-1] then e[0..k-1])
reg [4:0] c_poly; // 0..2k
reg [7:0] c_widx;
reg c_busy;
wire [7:0] c_nonce = {3'b0, c_poly}; // s:0..k-1 e:k..2k-1 == nonce
// slot: c_poly < k -> s_hat[c_poly], else e_hat[c_poly-k]
wire [SAW-1:0] c_slot = (c_poly < {2'b0, k_r}) ? (slot_s_rt + c_poly)
: (slot_e_rt + (c_poly - {2'b0, k_r}));
assign busy_o = (st != ST_IDLE);
assign done_o = (st == ST_DONE);
assign dbg_rho_o = rho_r;
assign dbg_sigma_o = sigma_r;
// ---- sha3_top in G mode: data_i = {K_byte, d} (d byte0 in [7:0]) ----
reg sha3_valid;
wire sha3_ready;
wire [511:0] sha3_hash;
wire sha3_vo;
reg sha3_ack; // consumer ready for hash
wire [511:0] g_data = {248'b0, 5'b0, k_r, d_i}; // data_i[263:256]=k, [255:0]=d
// ---- single shared sha3_top serving BOTH G and H ----
// G (ST_G) uses single-block mode (mb_en=0); H(ek) (ST_H) uses the
// multi-block absorb path (mb_en=1). These phases are disjoint in the
// top FSM, so one sha3_top (one keccak_core) is sufficient. mb_en and
// ready_i are muxed by phase; data_i/mode only matter while mb_en=0.
wire sha3_mb_en = (st == ST_H);
sha3_top u_sha3 (
.clk(clk), .rst_n(rst_n),
.mode(2'b00), // G = SHA3-512 (only used when mb_en=0)
.data_i(g_data),
.valid_i(sha3_valid),
.ready_o(sha3_ready),
.hash_o(sha3_hash),
.valid_o(sha3_vo),
.ready_i(sha3_mb_en ? h_ack : sha3_ack),
.mb_en(sha3_mb_en),
.mb_block_i(h_block_r),
.mb_valid_i(h_mbvalid),
.mb_last_i(h_mblast),
.mb_ready_o(h_mbready)
);
// ---- multi-block H(ek) state (SHA3-256, 6/9/12 blocks); fed to shared u_sha3 ----
reg [1087:0] h_block_r; // current pre-padded rate block
reg h_mbvalid;
reg h_mblast;
wire h_mbready;
wire [511:0] h_hash;
wire h_vo;
reg h_ack;
reg [255:0] hek_r; // captured H(ek)
reg [3:0] h_blk; // 0..H_NBLK-1 block index (up to 11 for K=4)
reg [7:0] h_byte; // 0..136 byte address being presented (assemble)
reg [1:0] h_phase; // 0=assemble 1=feed 2=wait-perm 3=done
// ek BRAM read is registered (1-cycle latency); assemble presents the
// address for h_byte this cycle and writes the byte that arrived (for the
// address presented last cycle) into h_block_r. Writeback pipeline regs:
reg h_wb_vld; // a byte is arriving this cycle
reg [7:0] h_wb_idx; // its position within the 136-byte block
reg [11:0] h_wb_g; // its global ek byte index
reg [7:0] h_wb_pad; // pad constant to use if g is out of ek range
reg h_wb_inek; // 1 if g is within ek range (use BRAM data)
// h_hash / h_vo are now served by the shared u_sha3 above (mb_en=1 during
// ST_H). They alias the single core's outputs; the H consumer logic below
// already gates on st==ST_H, and u_sha3's valid_o/hash_o are mb-selected.
assign h_hash = sha3_hash;
assign h_vo = sha3_vo;
// SHA3-256 over ek (ek_bytes_rt bytes): rate=136. Padded length = h_nblk_rt*136.
// pad: byte ek_bytes_rt = 0x06 (domain + first pad bit), last byte |= 0x80.
// byte b (0..135) of block blk: global g = blk*136 + b.
// ek bytes come from the ek BRAM (registered read); only the pad/zero bytes
// are constants, returned by h_padconst. Reads runtime ek_bytes_rt/h_last_rt.
function [7:0] h_padconst(input [3:0] blk, input [7:0] b);
integer g;
begin
g = blk*136 + b;
if (g == h_last_rt && g == ek_bytes_rt) h_padconst = 8'h86; // 0x06|0x80
else if (g == ek_bytes_rt) h_padconst = 8'h06;
else if (g == h_last_rt) h_padconst = 8'h80;
else h_padconst = 8'h00;
end
endfunction
// Global ek byte index for the address currently presented in ST_H assemble.
wire [11:0] h_g_addr = {8'd0, h_blk} * 12'd136 + {4'd0, h_byte};
// ek BRAM read-address mux: ST_H assemble drives it; otherwise debug readback.
// dbg_dk ek-region takes priority (its loop runs after the ek loop), so the
// single read port serves dbg_byte_o (ek loop) then dbg_dk_o (dk loop).
wire [11:0] dbgdk_ek_off = dbg_dk_idx_i - dk_bytes_rt; // offset within ek region
assign ek_rd_addr = (st == ST_H) ? h_g_addr[10:0] :
dbgdk_in_ek ? dbgdk_ek_off[10:0]
: dbg_byte_idx_i;
// dkp BRAM read-address mux: dbg_byte (sel=1) or dbg_dk (dkp region).
assign dkp_rd_addr = dbg_byte_sel_i ? dbg_byte_idx_i : dbg_dk_idx_i[10:0];
// ---- sample_ntt_sync: Â[i][j] = SampleNTT(rho || j || i) ----
reg snt_valid;
wire snt_ready;
wire [11:0] snt_coeff;
wire snt_vo;
wire snt_last;
reg snt_ack; // we accept coeffs
sample_ntt_sync #(.K(KMAX)) u_snt (
.clk(clk), .rst_n(rst_n),
.rho_i(rho_r),
.k_i(k_r),
.i_idx(a_i[1:0]),
.j_idx(a_j[1:0]),
.valid_i(snt_valid),
.ready_o(snt_ready),
.coeff_o(snt_coeff),
.valid_o(snt_vo),
.ready_i(snt_ack),
.last_o(snt_last)
);
// ---- sample_cbd_sync: s[i]=CBD3(PRF(sigma,i)), e[i]=CBD3(PRF(sigma,K+i)) ----
reg cbd_valid;
wire cbd_ready;
wire [11:0] cbd_coeff; // 12-bit signed (two's complement)
wire cbd_vo;
wire cbd_last;
reg cbd_ack;
sample_cbd_sync u_cbd (
.clk(clk), .rst_n(rst_n),
.seed_i(sigma_r),
.nonce_i(c_nonce),
.eta_i(eta1_rt),
.valid_i(cbd_valid),
.ready_o(cbd_ready),
.coeff_o(cbd_coeff),
.valid_o(cbd_vo),
.ready_i(cbd_ack),
.last_o(cbd_last)
);
// signed (two's complement) -> [0,Q): add Q when negative
wire [11:0] cbd_modq = cbd_coeff[11] ? (cbd_coeff + 12'(Q)) : cbd_coeff;
// ---- ntt_core: forward NTT (mode=0, no scaling) of s[i],e[i] in place ----
// N-stage bookkeeping: process slots S0,S1,E0,E1 (= SLOT_S0 + n_slot).
reg [4:0] n_slot; // 0..2K (process s_hat[0..K-1] then e_hat[0..K-1])
reg [8:0] n_ridx; // load read index 0..256
reg [7:0] n_widx; // output write index 0..255
reg n_valid; // feeding coeffs to ntt_core
reg n_pending; // waiting for ntt_core IDLE to start next slot
wire [SAW-1:0] n_slot_addr = slot_s_rt + n_slot; // s_hat then e_hat contiguous
wire ntt_ready;
wire [11:0] ntt_coeff;
wire ntt_vo;
wire ntt_done;
wire [11:0] ntt_in = polymem[n_slot_addr*256 + n_ridx[7:0]];
ntt_core u_ntt (
.clk(clk), .rst_n(rst_n),
.coeff_in(ntt_in),
.valid_i(n_valid),
.ready_o(ntt_ready),
.mode(1'b0), // forward NTT, no scaling
.coeff_out(ntt_coeff),
.valid_o(ntt_vo),
.ready_i(1'b1), // always accept output
.done_o(ntt_done)
);
// ---- poly_mul_sync: t_hat[i] = e_hat[i] + sum_j A_hat[i][j] o s_hat[j] ----
// M-stage bookkeeping. For each (i,j): LOAD 256 (A,shat) pairs, then accumulate
// 256 products into T_i (init from E_i when j==0, else from running T_i).
reg [2:0] m_i; // row 0..K (needs to reach K to exit)
reg [2:0] m_j; // col 0..K-1
reg [8:0] m_ld; // load index 0..256
reg [7:0] m_oidx; // output/accum index 0..255
reg m_loading; // 1 while streaming pairs into poly_mul
reg m_pending; // wait for poly_mul IDLE before next (i,j)
// ---- Stage 2f: byteEncode12 serializer ----
// Pack each poly (2 coeffs -> 3 bytes, LSB-first 12-bit). ek = t_hat[0..K-1]
// bytes || rho; dk_pke = s_hat[0..K-1] bytes. Walk coeff pairs per poly.
reg [4:0] e_poly; // 0..2K-1: [0,K) = t_hat -> ek; [K,2K) = s_hat -> dk_pke
reg [7:0] e_pair; // 0..127 coeff-pair within poly
reg [1:0] e_byte; // 0..2 byte within the current pair (BRAM: 1 write/cycle)
reg [9:0] e_rho; // 0..31 rho byte copy index (ek tail)
reg e_done; // serialization complete
// source poly slot: t_hat[e_poly] for ek half, s_hat[e_poly-K] for dk half
wire e_is_dk = (e_poly >= {1'b0, k_r});
wire [4:0] e_pidx = e_is_dk ? (e_poly - {1'b0, k_r}) : e_poly; // index within target
wire [SAW-1:0] e_slot = e_is_dk ? (slot_s_rt + e_pidx) : (slot_t_rt + e_pidx);
// two coeffs of the current pair
wire [11:0] e_c0 = polymem[e_slot*256 + {e_pair, 1'b0}];
wire [11:0] e_c1 = polymem[e_slot*256 + {e_pair, 1'b1}];
// 3 packed bytes
wire [7:0] e_b0 = e_c0[7:0];
wire [7:0] e_b1 = {e_c1[3:0], e_c0[11:8]};
wire [7:0] e_b2 = e_c1[11:4];
// byte base offset within target memory: poly index *384 (= 128 pairs *3)
wire [11:0] e_base = e_pidx * 12'd384;
wire [11:0] e_boff = e_base + {e_pair, 1'b0} + {2'b0, e_pair}; // pair*3
// BRAM write is 1 byte/cycle: select packed byte by e_byte sub-counter
wire [7:0] e_byte_d = (e_byte == 2'd0) ? e_b0 : (e_byte == 2'd1) ? e_b1 : e_b2;
wire [SAW-1:0] m_aslot = m_i*k_r + m_j; // A_hat[i][j] slot = i*k + j
wire [SAW-1:0] m_sslot = slot_s_rt + m_j; // s_hat[j]
wire [SAW-1:0] m_eslot = slot_e_rt + m_i; // e_hat[i]
wire [SAW-1:0] m_tslot = slot_t_rt + m_i; // t_hat[i]
reg pm_valid;
wire pm_ready;
wire [11:0] pm_coeff;
wire pm_vo;
wire [11:0] pm_a_in = polymem[m_aslot*256 + m_ld[7:0]];
wire [11:0] pm_b_in = polymem[m_sslot*256 + m_ld[7:0]];
poly_mul_sync u_pmul (
.clk(clk), .rst_n(rst_n),
.coeff_a_in(pm_a_in),
.coeff_b_in(pm_b_in),
.valid_i(pm_valid),
.ready_o(pm_ready),
.coeff_out(pm_coeff),
.valid_o(pm_vo),
.ready_i(1'b1)
);
// accumulator source: e_hat[i] for first term (j==0), else running t_hat[i]
wire [11:0] m_acc_src = (m_j == 2'd0) ? polymem[m_eslot*256 + m_oidx]
: polymem[m_tslot*256 + m_oidx];
// (a + b) mod Q (both < Q, sum < 2Q): one conditional subtract
wire [12:0] m_sum = {1'b0, m_acc_src} + {1'b0, pm_coeff};
wire [11:0] m_accq = (m_sum >= 13'(Q)) ? (m_sum - 13'(Q)) : m_sum[11:0];
always @(*) begin
st_next = st;
case (st)
ST_IDLE: if (start_i) st_next = ST_G;
ST_G: if (sha3_vo) st_next = ST_A;
ST_A: if (a_pair >= kk_rt) st_next = ST_C;
ST_C: if (c_poly >= {1'b0, k_r, 1'b0}) st_next = ST_N;
ST_N: if (n_slot >= {1'b0, k_r, 1'b0}) st_next = ST_M;
ST_M: if (m_i >= k_r) st_next = ST_E;
ST_E: if (e_done) st_next = ST_H;
ST_H: if (h_phase == 2'd3) st_next = ST_DONE;
ST_DONE: st_next = ST_IDLE;
default: st_next = ST_IDLE;
endcase
end
always @(posedge clk or negedge rst_n) begin
if (!rst_n) begin
st <= ST_IDLE;
k_r <= 3'd0;
rho_r <= 256'd0;
sigma_r <= 256'd0;
sha3_valid <= 1'b0;
sha3_ack <= 1'b0;
snt_valid <= 1'b0;
snt_ack <= 1'b0;
a_pair <= 5'd0;
a_i <= 3'd0;
a_j <= 3'd0;
a_widx <= 8'd0;
a_busy <= 1'b0;
cbd_valid <= 1'b0;
cbd_ack <= 1'b0;
c_poly <= 3'd0;
c_widx <= 8'd0;
c_busy <= 1'b0;
n_slot <= 3'd0;
n_ridx <= 9'd0;
n_widx <= 8'd0;
n_valid <= 1'b0;
n_pending <= 1'b0;
m_i <= 2'd0;
m_j <= 2'd0;
m_ld <= 9'd0;
m_oidx <= 8'd0;
m_loading <= 1'b0;
m_pending <= 1'b0;
pm_valid <= 1'b0;
e_poly <= 3'd0;
e_pair <= 8'd0;
e_byte <= 2'd0;
e_rho <= 10'd0;
e_done <= 1'b0;
ek_we <= 1'b0;
dkp_we <= 1'b0;
ek_wa <= 11'd0;
dkp_wa <= 11'd0;
ek_wd <= 8'd0;
dkp_wd <= 8'd0;
h_block_r <= 1088'd0;
h_mbvalid <= 1'b0;
h_mblast <= 1'b0;
h_ack <= 1'b0;
hek_r <= 256'd0;
h_blk <= 3'd0;
h_byte <= 8'd0;
h_phase <= 2'd0;
h_wb_vld <= 1'b0;
h_wb_idx <= 8'd0;
h_wb_g <= 12'd0;
h_wb_pad <= 8'd0;
h_wb_inek <= 1'b0;
end else begin
st <= st_next;
// BRAM write-enables default low; pulsed where a byte is written.
ek_we <= 1'b0;
dkp_we <= 1'b0;
// Kick off G when entering ST_G
if (st == ST_IDLE && start_i) begin
k_r <= k_i; // capture runtime ML-KEM param
sha3_valid <= 1'b1;
sha3_ack <= 1'b1;
end
// Drop valid once accepted
if (sha3_valid && sha3_ready) sha3_valid <= 1'b0;
// Capture rho/sigma when G completes; arm A stage
if (st == ST_G && sha3_vo) begin
rho_r <= sha3_hash[255:0]; // rho = G output bytes 0..31
sigma_r <= sha3_hash[511:256]; // sigma = bytes 32..63
sha3_ack <= 1'b0;
snt_valid <= 1'b1; // start first SampleNTT
snt_ack <= 1'b1;
a_pair <= 5'd0;
a_i <= 3'd0;
a_j <= 3'd0;
a_widx <= 8'd0;
a_busy <= 1'b0;
end
// ---- ST_A: drive SampleNTT, store 256 coeffs per pair ----
if (st == ST_A) begin
// mark busy once this pair's request accepted
if (snt_valid && snt_ready) begin
snt_valid <= 1'b0;
a_busy <= 1'b1;
end
// store each output coefficient only while busy (ignore stale last coeff from prior poly)
if (a_busy && snt_vo && snt_ack) begin
polymem[a_slot*256 + a_widx] <= snt_coeff;
if (snt_last) begin
// finished this poly; advance (i,j) in row-major order
a_pair <= a_pair + 5'd1;
a_widx <= 8'd0;
a_busy <= 1'b0;
if (a_j + 3'd1 < k_r) begin
a_j <= a_j + 3'd1;
end else begin
a_j <= 3'd0;
a_i <= a_i + 3'd1;
end
// start next SampleNTT if more pairs remain
if (a_pair + 5'd1 < kk_rt) snt_valid <= 1'b1;
end else begin
a_widx <= a_widx + 8'd1;
end
end
end
// Arm C stage when A finishes
if (st == ST_A && st_next == ST_C) begin
cbd_valid <= 1'b1;
cbd_ack <= 1'b1;
c_poly <= 3'd0;
c_widx <= 8'd0;
c_busy <= 1'b0;
end
// ---- ST_C: drive CBD, store 256 mod-q coeffs per poly ----
if (st == ST_C) begin
if (cbd_valid && cbd_ready) begin
cbd_valid <= 1'b0;
c_busy <= 1'b1;
end
if (c_busy && cbd_vo && cbd_ack) begin
polymem[c_slot*256 + c_widx] <= cbd_modq;
if (cbd_last) begin
c_poly <= c_poly + 3'd1;
c_widx <= 8'd0;
c_busy <= 1'b0;
if (c_poly + 3'd1 < {1'b0, k_r, 1'b0}) cbd_valid <= 1'b1;
end else begin
c_widx <= c_widx + 8'd1;
end
end
end
// Arm N stage when C finishes: start NTT on slot S0
if (st == ST_C && st_next == ST_N) begin
n_slot <= 3'd0;
n_ridx <= 9'd0;
n_widx <= 8'd0;
n_valid <= 1'b1; // begin loading first poly
n_pending <= 1'b0;
end
// ---- ST_N: forward NTT each of S0,S1,E0,E1 in place ----
if (st == ST_N) begin
// LOAD phase: stream 256 coeffs into ntt_core
if (n_valid && ntt_ready) begin
if (n_ridx == 9'd255) begin
n_valid <= 1'b0; // last coeff presented this cycle
n_ridx <= 9'd0;
end else begin
n_ridx <= n_ridx + 9'd1;
end
end
// OUTPUT phase: collect 256 results, write back to same slot
if (ntt_vo) begin
polymem[n_slot_addr*256 + n_widx] <= ntt_coeff;
n_widx <= n_widx + 8'd1; // wraps 255->0 after last
end
// Slot complete when ntt_core returns to DONE
if (ntt_done) begin
if (n_slot + 3'd1 < {1'b0, k_r, 1'b0}) begin
n_slot <= n_slot + 3'd1;
n_widx <= 8'd0;
n_pending <= 1'b1; // wait one cycle for core IDLE
end else begin
n_slot <= n_slot + 3'd1; // == 2K -> ST_DONE
end
end
// Kick next slot's load once core is back IDLE
if (n_pending && ntt_ready && !ntt_done) begin
n_valid <= 1'b1;
n_ridx <= 9'd0;
n_pending <= 1'b0;
end
end
// Arm M stage when N finishes: start first (i=0,j=0) poly_mul load
if (st == ST_N && st_next == ST_M) begin
m_i <= 2'd0;
m_j <= 2'd0;
m_ld <= 9'd0;
m_oidx <= 8'd0;
m_loading <= 1'b1;
m_pending <= 1'b0;
pm_valid <= 1'b1;
end
// ---- ST_M: t_hat[i] = e_hat[i] + sum_j A[i][j] o s_hat[j] ----
if (st == ST_M) begin
// LOAD: stream 256 (A,shat) pairs into poly_mul
if (m_loading && pm_valid && pm_ready) begin
if (m_ld == 9'd255) begin
pm_valid <= 1'b0; // last pair presented
m_loading <= 1'b0;
m_ld <= 9'd0;
m_oidx <= 8'd0;
end else begin
m_ld <= m_ld + 9'd1;
end
end
// ACCUMULATE: each product coeff += e_hat (j==0) or running t_hat
if (pm_vo) begin
polymem[m_tslot*256 + m_oidx] <= m_accq;
if (m_oidx == 8'd255) begin
// finished this (i,j) term; advance
if (m_j + 2'd1 < k_r) begin
m_j <= m_j + 2'd1;
m_pending <= 1'b1; // next term, same row
end else begin
m_j <= 2'd0;
m_i <= m_i + 2'd1; // next row (or == K -> DONE)
if (m_i + 2'd1 < k_r) m_pending <= 1'b1;
end
end else begin
m_oidx <= m_oidx + 8'd1;
end
end
// Start next (i,j) poly_mul load once core is IDLE again
if (m_pending && pm_ready && !pm_vo) begin
pm_valid <= 1'b1;
m_loading <= 1'b1;
m_ld <= 9'd0;
m_oidx <= 8'd0;
m_pending <= 1'b0;
end
end
// Arm E stage when M finishes
if (st == ST_M && st_next == ST_E) begin
e_poly <= 3'd0;
e_pair <= 8'd0;
e_byte <= 2'd0;
e_rho <= 10'd0;
e_done <= 1'b0;
end
// ---- ST_E: byteEncode12 t_hat -> ek, s_hat -> dk_pke, 1 byte/cycle ----
if (st == ST_E && !e_done) begin
if (e_poly < {1'b0, k_r, 1'b0}) begin
// write current byte (e_byte_d) to target BRAM
if (!e_is_dk) begin
ek_we <= 1'b1;
ek_wa <= e_boff[10:0] + {9'd0, e_byte};
ek_wd <= e_byte_d;
end else begin
dkp_we <= 1'b1;
dkp_wa <= e_boff[10:0] + {9'd0, e_byte};
dkp_wd <= e_byte_d;
end
// advance sub-counters
if (e_byte == 2'd2) begin
e_byte <= 2'd0;
if (e_pair == 8'd127) begin
e_pair <= 8'd0;
e_poly <= e_poly + 5'd1; // next poly or -> rho phase
end else begin
e_pair <= e_pair + 8'd1;
end
end else begin
e_byte <= e_byte + 2'd1;
end
end else begin
// rho copy: ek[384*K + r] = rho byte r (r = 0..31), 1 byte/cycle
ek_we <= 1'b1;
ek_wa <= dk_bytes_rt[10:0] + {1'b0, e_rho};
ek_wd <= rho_r[e_rho*8 +: 8];
if (e_rho == 10'd31) e_done <= 1'b1;
else e_rho <= e_rho + 10'd1;
end
end
// Arm H stage when E finishes
if (st == ST_E && st_next == ST_H) begin
h_blk <= 3'd0;
h_byte <= 8'd0;
h_phase <= 2'd0; // assemble
h_mbvalid<= 1'b0;
h_mblast <= 1'b0;
h_ack <= 1'b1; // ready to consume final digest
h_wb_vld <= 1'b0; // no pending writeback yet
end
// ---- ST_H: H(ek) via multi-block SHA3-256 (6/9/12 pre-padded blocks) ----
if (st == ST_H) begin
case (h_phase)
// assemble 136 bytes of block h_blk into h_block_r.
// ek BRAM read is registered: present addr for h_byte this
// cycle, write back the byte that arrived for the addr we
// presented last cycle (h_wb_*). h_byte runs 0..136 (one
// extra cycle to flush the final writeback).
2'd0: begin
// writeback the byte read for the previous address
if (h_wb_vld)
h_block_r[h_wb_idx*8 +: 8] <= h_wb_inek ? ek_rd_data : h_wb_pad;
if (h_byte <= 8'd135) begin
// set up writeback for the address presented this cycle
h_wb_vld <= 1'b1;
h_wb_idx <= h_byte;
h_wb_g <= h_g_addr;
h_wb_inek <= (h_g_addr < ek_bytes_rt);
h_wb_pad <= h_padconst(h_blk, h_byte);
h_byte <= h_byte + 8'd1;
end else begin
// h_byte==136: final writeback (for byte 135) done above
h_wb_vld <= 1'b0;
h_byte <= 8'd0;
h_mbvalid <= 1'b1;
h_mblast <= (h_blk == h_nblk_rt - 4'd1);
h_phase <= 2'd1; // feed
end
end
// feed: hold valid until accepted (mb_ready drops)
2'd1: begin
if (h_mbvalid && !h_mbready) begin
h_mbvalid <= 1'b0;
h_mblast <= 1'b0;
h_phase <= 2'd2; // wait permute
end
end
// wait permute done: ready again (more blocks) or digest valid (last)
2'd2: begin
if (h_vo) begin
hek_r <= h_hash[255:0];
h_phase <= 2'd3; // done
end else if (h_mbready) begin
h_blk <= h_blk + 3'd1;
h_phase <= 2'd0; // assemble next block
end
end
default: ; // 2'd3 done: hold
endcase
end
end
end
endmodule