ntt works

v2/kyber/kyber.cc

@@ -348,10 +348,10 @@ byte bit_reverse(byte b) {
 
 bool ntt_base_mult(int q, int g, int& in1a, int& in1b,
         int& in2a, int& in2b, int* outa, int* outb) {
-  int u0 = ((in1a * in2a) % q + (((in1b * in2b) %q) * g) % q) % q;
-  int u1 = (((in1a * in2b) % q) + ((in2a * in1a) %q)) % q;
-  *outa = u0;
-  *outb = u1;
+  int u1 = ((in1a * in2a) % q + (((in1b * in2b) %q) * g) % q) % q;
+  int u2 = (((in1a * in2b) % q) + ((in2a * in1a) %q)) % q;
+  *outa = u1;
+  *outb = u2;
   return true;
 }
 
@@ -407,7 +407,7 @@ bool sample_ntt(int q, int l, int b_len, byte* b, int* out_len, short int* out)
 }
 
 bool sample_poly_cbd(int q, int eta, int l, int b_len, byte* b,
-	int* out_len, short int* out) {
+        int* out_len, short int* out) {
   if (b_len * NBITSINBYTE < l)
     return false;
 
@@ -435,19 +435,18 @@ bool ntt(int g, coefficient_vector& in, coefficient_vector* out) {
   int k = 1;
   coefficient_set_vector(in, out);
 
-  for (int l = 128; l >= 2; l /=2) {
+  for (int l = 128; l >= 2; l /= 2) {
     for (int s = 0; s < in.len_; s+= 2 * l) {
       byte bb = bit_reverse((byte)k);
       bb >>= 1;
       int z = exp_in_ntt(in.q_, (int) bb, g);
       k++;
       for (int j = s; j < (s + l); j++) {
-        // FIX
-        //int t = (z * read_ntt(out->c_, j + l)) % in.q_;
-        //int s1 = (read_ntt(out->c_, j) + (in.q_ - t)) % in.q_;
-        //write_ntt(j + l, s1, &out->c_);
-        //short int s2 = (read_ntt(out->c_, j) + t) % in.q_;
-        //write_ntt(j, s2, &out->c_);
+        int t = (z * out->c_[j + l]) % in.q_;
+        int s1 = (out->c_[j] + (in.q_ - t)) % in.q_;
+        out->c_[j + l]= s1;
+        int s2 = (out->c_[j] + t) % in.q_;
+        out->c_[j] = s2; 
       }
     }
   }
@@ -465,15 +464,14 @@ bool ntt_inv(int g, coefficient_vector& in, coefficient_vector* out) {
     for (int s = 0; s < 256; s += 2 * l) {
       byte bb = bit_reverse((byte)k);
       bb >>= 1;
-      int z = exp_in_ntt(in.q_, bb, g);
+      int z = exp_in_ntt(in.q_, (int)bb, g);
       k--;
-      for (int j = s; j < s + l; j += 2 * l) {
-        // FIX
-        // short int t = read_ntt(out->c_, j);
-        // short int s1 = (in.q_ + (z *  read_ntt(out->c_, j + l))  - t ) % in.q_;
-        // write_ntt(j, s1, &out->c_);
-        // short int s2 = (in.q_ + ((z *  read_ntt(out->c_, j + l) % in.q_))  - t ) % in.q_;
-        // write_ntt(j + l, s2, &out->c_);
+      for (int j = s; j < s + l; j++) {
+        int t = out->c_[j];
+        int s1 = (t + out->c_[j+l]) % in.q_;
+        out->c_[j] = s1;
+        int s2 = (z *  (out->c_[j + l] + in.q_ - t)) % in.q_;
+        out->c_[j + l] = s2;
       }
     }
   }
@@ -483,21 +481,21 @@ bool ntt_inv(int g, coefficient_vector& in, coefficient_vector* out) {
   return true;
 }
 
-bool ntt_mult(short int g, coefficient_vector& in1, coefficient_vector& in2, coefficient_vector* out) {
+bool ntt_mult(int g, coefficient_vector& in1, coefficient_vector& in2, coefficient_vector* out) {
   if (in1.len_ != in2.len_ || in1.len_ != out->len_)
     return false;
   if (in1.q_ != in2.q_ || in1.q_ != out->q_)
     return false;
   int t = 0;
-  for (int i = 0; i < in1.len_; i++) {
+  for (int i = 0; i < in1.len_; i += 2) {
     int e = (short int)(bit_reverse(i/2)>>1);
     e *= 2;
     e += 1;
     t = exp_in_ntt(in1.q_, e, g);
-#if 0
-    if (!ntt_base_mult(in1.q_, g, in1.c_[i], in2.c_[i], &(out->c_[i])))
+    if (!ntt_base_mult(in1.q_, g, in1.c_[i], in1.c_[i + 1],
+            in2.c_[i], in2.c_[i + 1],
+            &(out->c_[i]), &(out->c_[i + 1])))
       return false;
-#endif
   }
   return true;
 }

v2/kyber/test_kyber.cc

@@ -261,10 +261,10 @@ bool test_kyber_support() {
   print_kyber_parameters(p);
 
   int g = 17;
-  int i1a = 0;
-  int i2a = 0;
-  int i1b = 0;
-  int i2b = 0;
+  int i1a = 2;
+  int i2a = 5;
+  int i1b = 1;
+  int i2b = 3;
   int oa = 0;
   int ob = 0;
   if (!ntt_base_mult(p.q_, g, i1a, i1b, i2a, i2b, &oa, &ob)) {
@@ -386,20 +386,14 @@ bool test_kyber_support() {
     printf("\n");
   }
 
-#if 0
   for (int i = 0; i < 256; i++) {
     if (ntt_in.c_[i] !=  ntt_inv_out.c_[i]) {
       printf("input and ntt_inv(ntt(input)) do not match at %d\n", i);
       return false;
     }
   }
-#endif
 
   /*
-  if (!ntt_add(coefficient_vector& in1, coefficient_vector& in2, coefficient_vector* out)) {
-    printf("Could not inverse ntt_add\n");
-    return false;
-  }
   if (!ntt_mult(short int g, coefficient_vector& in1, coefficient_vector& in2, coefficient_vector* out)) {
     printf("Could not inverse ntt_mult\n");
     return false;