First commit, Vystem v0.1

Blastproof/initfsgen/merkle.c

@@ -0,0 +1,61 @@
+#include <stdint.h>
+#include <string.h>
+
+#include "utils.h"
+#include "utilsx1.h"
+#include "wots.h"
+#include "wotsx1.h"
+#include "merkle.h"
+#include "address.h"
+#include "params.h"
+
+/*
+ * This generates a Merkle signature (WOTS signature followed by the Merkle
+ * authentication path).  This is in this file because most of the complexity
+ * is involved with the WOTS signature; the Merkle authentication path logic
+ * is mostly hidden in treehashx4
+ */
+void merkle_sign(uint8_t *sig, unsigned char *root,
+                 const spx_ctx *ctx,
+                 uint32_t wots_addr[8], uint32_t tree_addr[8],
+                 uint32_t idx_leaf)
+{
+    unsigned char *auth_path = sig + SPX_WOTS_BYTES;
+    struct leaf_info_x1 info = { 0 };
+    unsigned steps[ SPX_WOTS_LEN ];
+
+    info.wots_sig = sig;
+    chain_lengths(steps, root);
+    info.wots_steps = steps;
+
+    set_type(&tree_addr[0], SPX_ADDR_TYPE_HASHTREE);
+    set_type(&info.pk_addr[0], SPX_ADDR_TYPE_WOTSPK);
+    copy_subtree_addr(&info.leaf_addr[0], wots_addr);
+    copy_subtree_addr(&info.pk_addr[0], wots_addr);
+
+    info.wots_sign_leaf = idx_leaf;
+
+    treehashx1(root, auth_path, ctx,
+                idx_leaf, 0,
+                SPX_TREE_HEIGHT,
+                wots_gen_leafx1,
+                tree_addr, &info);
+}
+
+/* Compute root node of the top-most subtree. */
+void merkle_gen_root(unsigned char *root, const spx_ctx *ctx)
+{
+    /* We do not need the auth path in key generation, but it simplifies the
+       code to have just one treehash routine that computes both root and path
+       in one function. */
+    unsigned char auth_path[SPX_TREE_HEIGHT * SPX_N + SPX_WOTS_BYTES];
+    uint32_t top_tree_addr[8] = {0};
+    uint32_t wots_addr[8] = {0};
+
+    set_layer_addr(top_tree_addr, SPX_D - 1);
+    set_layer_addr(wots_addr, SPX_D - 1);
+
+    merkle_sign(auth_path, root, ctx,
+                wots_addr, top_tree_addr,
+                (uint32_t)~0 /* ~0 means "don't bother generating an auth path */ );
+}