1 files changed, 40 insertions, 0 deletions
diff --git a/src/lib/pubkey/xmss/xmss_wots_common_ops.cpp b/src/lib/pubkey/xmss/xmss_wots_common_ops.cpp
new file mode 100644
index 000000000..5d0349677
--- /dev/null
+++ b/src/lib/pubkey/xmss/xmss_wots_common_ops.cpp
@@ -0,0 +1,40 @@
+/**
+ * XMSS WOTS Common Ops
+ * Operations shared by XMSS WOTS signature generation and verification
+ * operations.
+ *
+ * (C) 2016 Matthias Gierlings
+ *
+ * Botan is released under the Simplified BSD License (see license.txt)
+ **/
+
+#include <botan/internal/xmss_wots_common_ops.h>
+
+namespace Botan {
+
+void
+XMSS_WOTS_Common_Ops::chain(secure_vector<byte>& result,
+                            size_t start_idx,
+                            size_t steps,
+                            XMSS_Address& adrs,
+                            const secure_vector<byte>& seed)
+   {
+   for(size_t i = start_idx;
+         i < (start_idx + steps) && i < m_wots_params.wots_parameter();
+         i++)
+      {
+      adrs.set_hash_address(i);
+
+      //Calculate tmp XOR bitmask
+      adrs.set_key_mask_mode(XMSS_Address::Key_Mask::Mask_Mode);
+      xor_buf(result, m_hash.prf(seed, adrs.bytes()), result.size());
+
+      // Calculate key
+      adrs.set_key_mask_mode(XMSS_Address::Key_Mask::Key_Mode);
+
+      //Calculate f(key, tmp XOR bitmask)
+      m_hash.f(result, m_hash.prf(seed, adrs.bytes()), result);
+      }
+   }
+
+}