Rename hash functions to tweaked hashes

Since there's a tweak being introduced, this should be reflected
in the name of the functions.

hash.c

@@ -83,9 +83,9 @@ int hash_message(const xmss_params *params, unsigned char *out,
 /**
  * We assume the left half is in in[0]...in[n-1]
  */
-int hash_h(const xmss_params *params,
-           unsigned char *out, const unsigned char *in,
-           const unsigned char *pub_seed, uint32_t addr[8])
+int thash_h(const xmss_params *params,
+            unsigned char *out, const unsigned char *in,
+            const unsigned char *pub_seed, uint32_t addr[8])
 {
     unsigned char buf[4 * params->n];
     unsigned char bitmask[2 * params->n];
@@ -115,9 +115,9 @@ int hash_h(const xmss_params *params,
     return core_hash(params, out, buf, 4 * params->n);
 }
 
-int hash_f(const xmss_params *params,
-           unsigned char *out, const unsigned char *in,
-           const unsigned char *pub_seed, uint32_t addr[8])
+int thash_f(const xmss_params *params,
+            unsigned char *out, const unsigned char *in,
+            const unsigned char *pub_seed, uint32_t addr[8])
 {
     unsigned char buf[3 * params->n];
     unsigned char bitmask[params->n];

hash.h

@@ -15,13 +15,13 @@ int h_msg(const xmss_params *params,
           const unsigned char *in, unsigned long long inlen,
           const unsigned char *key, const unsigned int keylen);
 
-int hash_h(const xmss_params *params,
-           unsigned char *out, const unsigned char *in,
-           const unsigned char *pub_seed, uint32_t addr[8]);
+int thash_h(const xmss_params *params,
+            unsigned char *out, const unsigned char *in,
+            const unsigned char *pub_seed, uint32_t addr[8]);
 
-int hash_f(const xmss_params *params,
-           unsigned char *out, const unsigned char *in,
-           const unsigned char *pub_seed, uint32_t addr[8]);
+int thash_f(const xmss_params *params,
+            unsigned char *out, const unsigned char *in,
+            const unsigned char *pub_seed, uint32_t addr[8]);
 
 int hash_message(const xmss_params *params, unsigned char *out,
                  const unsigned char *R, const unsigned char *root,

wots.c

@@ -43,7 +43,7 @@ static void gen_chain(const xmss_params *params,
     /* Iterate 'steps' calls to the hash function. */
     for (i = start; i < (start+steps) && i < params->wots_w; i++) {
         set_hash_addr(addr, i);
-        hash_f(params, out, out, pub_seed, addr);
+        thash_f(params, out, out, pub_seed, addr);
     }
 }
 

xmss_commons.c

@@ -68,7 +68,7 @@ void l_tree(const xmss_params *params,
         for (i = 0; i < parent_nodes; i++) {
             set_tree_index(addr, i);
             /* Hashes the nodes at (i*2)*params->n and (i*2)*params->n + 1 */
-            hash_h(params, wots_pk + i*params->n,
+            thash_h(params, wots_pk + i*params->n,
                            wots_pk + (i*2)*params->n, pub_seed, addr);
         }
         /* If the row contained an odd number of nodes, the last node was not
@@ -117,11 +117,11 @@ static void compute_root(const xmss_params *params, unsigned char *root,
 
         /* Pick the right or left neighbor, depending on parity of the node. */
         if (leafidx & 1) {
-            hash_h(params, buffer + params->n, buffer, pub_seed, addr);
+            thash_h(params, buffer + params->n, buffer, pub_seed, addr);
             memcpy(buffer, auth_path, params->n);
         }
         else {
-            hash_h(params, buffer, buffer, pub_seed, addr);
+            thash_h(params, buffer, buffer, pub_seed, addr);
             memcpy(buffer + params->n, auth_path, params->n);
         }
         auth_path += params->n;
@@ -131,7 +131,7 @@ static void compute_root(const xmss_params *params, unsigned char *root,
     set_tree_height(addr, params->tree_height - 1);
     leafidx >>= 1;
     set_tree_index(addr, leafidx);
-    hash_h(params, root, buffer, pub_seed, addr);
+    thash_h(params, root, buffer, pub_seed, addr);
 }
 
 /**

xmss_core.c

@@ -69,7 +69,7 @@ static void treehash(const xmss_params *params,
                from the fact that we address the hash function calls. */
             set_tree_height(node_addr, heights[offset - 1]);
             set_tree_index(node_addr, tree_idx);
-            hash_h(params, stack + (offset-2)*params->n,
+            thash_h(params, stack + (offset-2)*params->n,
                            stack + (offset-2)*params->n, pub_seed, node_addr);
             offset--;
             /* Note that the top-most node is now one layer higher. */

xmss_core_fast.c

@@ -269,7 +269,7 @@ static void treehash_init(const xmss_params *params,
             }
             set_tree_height(node_addr, stacklevels[stackoffset-1]);
             set_tree_index(node_addr, (idx >> (stacklevels[stackoffset-1]+1)));
-            hash_h(params, stack+(stackoffset-2)*params->n, stack+(stackoffset-2)*params->n, pub_seed, node_addr);
+            thash_h(params, stack+(stackoffset-2)*params->n, stack+(stackoffset-2)*params->n, pub_seed, node_addr);
             stacklevels[stackoffset-2]++;
             stackoffset--;
         }
@@ -310,7 +310,7 @@ static void treehash_update(const xmss_params *params,
         memcpy(nodebuffer, state->stack + (state->stackoffset-1)*params->n, params->n);
         set_tree_height(node_addr, nodeheight);
         set_tree_index(node_addr, (treehash->next_idx >> (nodeheight+1)));
-        hash_h(params, nodebuffer, nodebuffer, pub_seed, node_addr);
+        thash_h(params, nodebuffer, nodebuffer, pub_seed, node_addr);
         nodeheight++;
         treehash->stackusage--;
         state->stackoffset--;
@@ -422,7 +422,7 @@ static char bds_state_update(const xmss_params *params,
         }
         set_tree_height(node_addr, state->stacklevels[state->stackoffset-1]);
         set_tree_index(node_addr, (idx >> (state->stacklevels[state->stackoffset-1]+1)));
-        hash_h(params, state->stack+(state->stackoffset-2)*params->n, state->stack+(state->stackoffset-2)*params->n, pub_seed, node_addr);
+        thash_h(params, state->stack+(state->stackoffset-2)*params->n, state->stack+(state->stackoffset-2)*params->n, pub_seed, node_addr);
 
         state->stacklevels[state->stackoffset-2]++;
         state->stackoffset--;
@@ -482,7 +482,7 @@ static void bds_round(const xmss_params *params,
     else {
         set_tree_height(node_addr, (tau-1));
         set_tree_index(node_addr, leaf_idx >> tau);
-        hash_h(params, state->auth + tau * params->n, buf, pub_seed, node_addr);
+        thash_h(params, state->auth + tau * params->n, buf, pub_seed, node_addr);
         for (i = 0; i < tau; i++) {
             if (i < params->tree_height - params->bds_k) {
                 memcpy(state->auth + i * params->n, state->treehash[i].node, params->n);