Core/Authserver: Authserver cleanup (PR#25093)

- Fix a handful of 1/256 bugs with most significant byte zero in BigNumber
- Get rid of (most of) the C-style arrays in authserver
- CryptoRandom as a unified source for cryptographic randomness
- Bring our other crypto APIs into 2020
- BigNumber usability improvements
- Authserver is now actually readable as a result of all of the above

1 files changed, 60 insertions, 0 deletions

diff --git a/src/common/Cryptography/SessionKeyGenerator.h b/src/common/Cryptography/SessionKeyGenerator.h
new file mode 100644
index 00000000000..af787358981
--- /dev/null
+++ b/src/common/Cryptography/SessionKeyGenerator.h
@@ -0,0 +1,60 @@
+/*
+ * This file is part of the TrinityCore Project. See AUTHORS file for Copyright information
+ *
+ * This program is free software; you can redistribute it and/or modify it
+ * under the terms of the GNU General Public License as published by the
+ * Free Software Foundation; either version 2 of the License, or (at your
+ * option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful, but WITHOUT
+ * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
+ * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for
+ * more details.
+ *
+ * You should have received a copy of the GNU General Public License along
+ * with this program. If not, see <http://www.gnu.org/licenses/>.
+ */
+
+#include <cstring>
+#include "CryptoHash.h"
+
+#ifndef TRINITY_SESSIONKEYGENERATOR_HPP
+#define TRINITY_SESSIONKEYGENERATOR_HPP
+
+template <typename Hash>
+class SessionKeyGenerator
+{
+    public:
+        template <typename C>
+        SessionKeyGenerator(C const& buf) :
+            o0it(o0.begin())
+        {
+            uint8 const* data = std::data(buf);
+            size_t const len = std::size(buf);
+            size_t const halflen = (len / 2);
+
+            o1 = Hash::GetDigestOf(data, halflen);
+            o2 = Hash::GetDigestOf(data + halflen, len - halflen);
+            o0 = Hash::GetDigestOf(o1, o0, o2);
+        }
+
+        void Generate(uint8* buf, uint32 sz)
+        {
+            for (uint32 i = 0; i < sz; ++i)
+            {
+                if (o0it == o0.end())
+                {
+                    o0 = Hash::GetDigestOf(o1, o0, o2);
+                    o0it = o0.begin();
+                }
+
+                buf[i] = *(o0it++);
+            }
+        }
+
+    private:
+        typename Hash::Digest o0, o1, o2;
+        typename Hash::Digest::const_iterator o0it;
+    };
+
+#endif