1 files changed, 70 insertions, 0 deletions
diff --git a/wsutil/xtea.c b/wsutil/xtea.c
new file mode 100644
index 00000000..b98de5f5
--- /dev/null
+++ b/wsutil/xtea.c
@@ -0,0 +1,70 @@
+/* xtea.c
+ * Implementation of XTEA cipher
+ * By Ahmad Fatoum <ahmad[AT]a3f.at>
+ * Copyright 2017 Ahmad Fatoum
+ *
+ * Wireshark - Network traffic analyzer
+ * By Gerald Combs <gerald@wireshark.org>
+ * Copyright 1998 Gerald Combs
+ *
+ * SPDX-License-Identifier: GPL-2.0-or-later
+ */
+
+#include "xtea.h"
+
+#include <string.h>
+
+#include "pint.h"
+
+void decrypt_xtea_ecb(uint8_t plaintext[8], const uint8_t ciphertext[8], const uint32_t key[4], unsigned num_rounds)
+{
+    unsigned i;
+    uint32_t v[2], delta = 0x9E3779B9, sum = delta * num_rounds;
+
+    v[0] = pntoh32(&ciphertext[0]);
+    v[1] = pntoh32(&ciphertext[4]);
+
+    for (i = 0; i < num_rounds; i++) {
+        v[1] -= (((v[0] << 4) ^ (v[0] >> 5)) + v[0]) ^ (sum + key[(sum >> 11) & 3]);
+        sum -= delta;
+        v[0] -= (((v[1] << 4) ^ (v[1] >> 5)) + v[1]) ^ (sum + key[sum & 3]);
+    }
+
+    v[0] = GUINT32_TO_BE(v[0]);
+    v[1] = GUINT32_TO_BE(v[1]);
+
+    memcpy(plaintext, v, sizeof v);
+}
+
+void decrypt_xtea_le_ecb(uint8_t plaintext[8], const uint8_t ciphertext[8], const uint32_t key[4], unsigned num_rounds)
+{
+    unsigned i;
+    uint32_t v[2], delta = 0x9E3779B9, sum = delta * num_rounds;
+
+    v[0] = pletoh32(&ciphertext[0]);
+    v[1] = pletoh32(&ciphertext[4]);
+
+    for (i = 0; i < num_rounds; i++) {
+        v[1] -= (((v[0] << 4) ^ (v[0] >> 5)) + v[0]) ^ (sum + key[(sum >> 11) & 3]);
+        sum -= delta;
+        v[0] -= (((v[1] << 4) ^ (v[1] >> 5)) + v[1]) ^ (sum + key[sum & 3]);
+    }
+
+    v[0] = GUINT32_TO_LE(v[0]);
+    v[1] = GUINT32_TO_LE(v[1]);
+
+    memcpy(plaintext, v, sizeof v);
+}
+
+/*
+ * Editor modelines  -  https://www.wireshark.org/tools/modelines.html
+ *
+ * Local variables:
+ * c-basic-offset: 4
+ * tab-width: 8
+ * indent-tabs-mode: nil
+ * End:
+ *
+ * vi: set shiftwidth=4 tabstop=8 expandtab:
+ * :indentSize=4:tabSize=8:noTabs=true:
+ */