Everywhere: Hoist the Libraries folder to the top-level

Author: https://github.com/trflynn89
Commit: 93712b24bf
Pull-request: https://github.com/LadybirdBrowser/ladybird/pull/2256
Reviewed-by: https://github.com/sideshowbarker

Libraries/LibCrypto/NumberTheory/ModularFunctions.h

@@ -0,0 +1,49 @@
+/*
+ * Copyright (c) 2020, Ali Mohammad Pur <mpfard@serenityos.org>
+ *
+ * SPDX-License-Identifier: BSD-2-Clause
+ */
+
+#pragma once
+
+#include <AK/Random.h>
+#include <LibCrypto/BigInt/UnsignedBigInteger.h>
+
+namespace Crypto::NumberTheory {
+
+UnsignedBigInteger Mod(UnsignedBigInteger const& a, UnsignedBigInteger const& b);
+UnsignedBigInteger ModularInverse(UnsignedBigInteger const& a_, UnsignedBigInteger const& b);
+UnsignedBigInteger ModularPower(UnsignedBigInteger const& b, UnsignedBigInteger const& e, UnsignedBigInteger const& m);
+
+// Note: This function _will_ generate extremely huge numbers, and in doing so,
+//       it will allocate and free a lot of memory!
+//       Please use |ModularPower| if your use-case is modexp.
+template<typename IntegerType>
+static IntegerType Power(IntegerType const& b, IntegerType const& e)
+{
+    IntegerType ep { e };
+    IntegerType base { b };
+    IntegerType exp { 1 };
+
+    while (!(ep < IntegerType { 1 })) {
+        if (ep.words()[0] % 2 == 1)
+            exp.set_to(exp.multiplied_by(base));
+
+        // ep = ep / 2;
+        ep.set_to(ep.shift_right(1));
+
+        // base = base * base
+        base.set_to(base.multiplied_by(base));
+    }
+
+    return exp;
+}
+
+UnsignedBigInteger GCD(UnsignedBigInteger const& a, UnsignedBigInteger const& b);
+UnsignedBigInteger LCM(UnsignedBigInteger const& a, UnsignedBigInteger const& b);
+
+UnsignedBigInteger random_number(UnsignedBigInteger const& min, UnsignedBigInteger const& max_excluded);
+bool is_probably_prime(UnsignedBigInteger const& p);
+UnsignedBigInteger random_big_prime(size_t bits);
+
+}