make Feistel random

Author: Aqua-Dream

Feistel.cpp

@@ -2,12 +2,13 @@
 #include "Feistel.h"
 #include "blake3.h"
 #include <stdexcept>
+#include <random>
 
-Feistel::Feistel(int64_t domain_size, int num_rounds)
+Feistel::Feistel(int64_t domain_size, int num_rounds): domain_size{domain_size}, num_rounds{num_rounds}
 {
-    this->domain_size = domain_size;
-    this->base = (int)ceil(log2(domain_size) / 2);
-    this->num_rounds = num_rounds;
+    base = (int)ceil(log2(domain_size) / 2);
+    std::random_device dev;
+    seed = dev();
 }
 
 int64_t Feistel::encrypt(int64_t input)
@@ -21,7 +22,7 @@ int64_t Feistel::encrypt(int64_t input)
     for (int i = 0; i < num_rounds; i++)
     {
         buffer[0] = r;
-        buffer[1] = i;
+        buffer[1] = i ^ seed;
         blake3_hasher_init(&hasher);
         blake3_hasher_update(&hasher, buffer, 2 * sizeof(int64_t));
         blake3_hasher_finalize(&hasher, (uint8_t *)buffer, 2 * sizeof(int64_t));

Feistel.h

@@ -12,6 +12,6 @@ class Feistel
 
 private:
     int64_t domain_size;
-    int base, num_rounds;
+    int base, num_rounds, seed;
     int64_t encrypt(int64_t input);
 };