1 files changed, 77 insertions, 0 deletions
diff --git a/doc/examples/ressol.cpp b/doc/examples/ressol.cpp
new file mode 100644
index 000000000..9fedc8115
--- /dev/null
+++ b/doc/examples/ressol.cpp
@@ -0,0 +1,77 @@
+#include <botan/numthry.h>
+
+using namespace Botan;
+
+#include <iostream>
+
+void test_ressol(const BigInt& p, RandomNumberGenerator& rng)
+   {
+   std::cout << p << std::endl;
+
+   //   const BigInt p_16 = p / 16;
+
+   int noroot = 0, false_result = 0;
+
+   for(int j = 0; j != 1000; ++j)
+      {
+      BigInt x = random_integer(rng, 0, p);
+      //if(x % p_16 == 0)
+      //std::cout << "p = " << p << " x = " << x << "\n";
+
+      BigInt sqrt_x = ressol(x, p);
+
+      if(sqrt_x < 0)
+         {
+         ++noroot;
+         continue;
+         }
+
+      BigInt check = square(sqrt_x) % p;
+
+      if(check != x % p)
+         {
+         std::cout << "FAIL "
+                   << "x = " << x << "; "
+                   << "p = " << p << "; "
+                   << "s = " << sqrt_x << "; "
+                   << "s^2%p = " << check << "\n";
+         ++false_result;
+         }
+      }
+   /*
+   std::cout << "nomatch=" << nomatch << " "
+             << "noroot=" << noroot << " "
+             << "false=" << false_result << "\n";
+   */
+   }
+
+int main()
+   {
+   RandomNumberGenerator* rng = RandomNumberGenerator::make_rng();
+
+#if 0
+   std::cout << ressol(8, 17) << "\n";
+   std::cout << ressol_orig(8, 17) << "\n";
+#endif
+
+#if 1
+   for(int j = 16; j != 1024; ++j)
+      {
+      std::cout << "Round " << j << "\n";
+      BigInt p = random_prime(*rng, j);
+      test_ressol(p, *rng);
+      //printf("%d\n", j);
+
+
+      }
+#endif
+   /*
+   for(u32bit j = 9; j != PRIME_TABLE_SIZE; ++j)
+      {
+      std::cout << "PRIME[" << j << "] == " << PRIMES[j] << std::endl;
+      //printf("%d - ", PRIMES[j]);
+      test_ressol(PRIMES[j], *rng);
+      //printf("\n");
+      }
+   */
+   }