1 files changed, 50 insertions, 0 deletions
diff --git a/src/common/Cryptography/TOTP.cpp b/src/common/Cryptography/TOTP.cpp
new file mode 100644
index 00000000000..9e89c212af4
--- /dev/null
+++ b/src/common/Cryptography/TOTP.cpp
@@ -0,0 +1,50 @@
+/*
+ * 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 "TOTP.h"
+#include <cstring>
+#include <openssl/evp.h>
+#include <openssl/hmac.h>
+
+static constexpr uint32 TOTP_INTERVAL = 30;
+static constexpr uint32 HMAC_RESULT_SIZE = 20;
+/*static*/ uint32 Trinity::Crypto::TOTP::GenerateToken(TOTP::Secret const& secret, time_t timestamp)
+{
+    timestamp /= TOTP_INTERVAL;
+    unsigned char challenge[8];
+    for (int i = 8; i--; timestamp >>= 8)
+        challenge[i] = timestamp;
+
+    unsigned char digest[HMAC_RESULT_SIZE];
+    uint32 digestSize = HMAC_RESULT_SIZE;
+    HMAC(EVP_sha1(), secret.data(), secret.size(), challenge, 8, digest, &digestSize);
+
+    uint32 offset = digest[19] & 0xF;
+    uint32 truncated = (digest[offset] << 24) | (digest[offset + 1] << 16) | (digest[offset + 2] << 8) | (digest[offset + 3]);
+    truncated &= 0x7FFFFFFF;
+    return (truncated % 1000000);
+}
+
+/*static*/ bool Trinity::Crypto::TOTP::ValidateToken(TOTP::Secret const& secret, uint32 token)
+{
+    time_t now = time(nullptr);
+    return (
+        (token == GenerateToken(secret, now - TOTP_INTERVAL)) ||
+        (token == GenerateToken(secret, now)) ||
+        (token == GenerateToken(secret, now + TOTP_INTERVAL))
+    );
+}