First commit, Vystem v0.1

2026-03-31 22:15:00 +02:00
commit e15daed8c0
462 changed files with 134655 additions and 0 deletions
--- a/Blastproof/initfsgen/wots.c
+++ b/Blastproof/initfsgen/wots.c
@@ -0,0 +1,112 @@
+#include <stdint.h>
+#include <string.h>
+
+#include "utils.h"
+#include "utilsx1.h"
+#include "hash.h"
+#include "thash.h"
+#include "wots.h"
+#include "wotsx1.h"
+#include "address.h"
+#include "params.h"
+
+// TODO clarify address expectations, and make them more uniform.
+// TODO i.e. do we expect types to be set already?
+// TODO and do we expect modifications or copies?
+
+/**
+ * Computes the chaining function.
+ * out and in have to be n-byte arrays.
+ *
+ * Interprets in as start-th value of the chain.
+ * addr has to contain the address of the chain.
+ */
+static void gen_chain(unsigned char *out, const unsigned char *in,
+                      unsigned int start, unsigned int steps,
+                      const spx_ctx *ctx, uint32_t addr[8])
+{
+    uint32_t i;
+
+    /* Initialize out with the value at position 'start'. */
+    memcpy(out, in, SPX_N);
+
+    /* Iterate 'steps' calls to the hash function. */
+    for (i = start; i < (start+steps) && i < SPX_WOTS_W; i++) {
+        set_hash_addr(addr, i);
+        thash(out, out, 1, ctx, addr);
+    }
+}
+
+/**
+ * base_w algorithm as described in draft.
+ * Interprets an array of bytes as integers in base w.
+ * This only works when log_w is a divisor of 8.
+ */
+static void base_w(unsigned int *output, const int out_len,
+                   const unsigned char *input)
+{
+    int in = 0;
+    int out = 0;
+    unsigned char total;
+    int bits = 0;
+    int consumed;
+
+    for (consumed = 0; consumed < out_len; consumed++) {
+        if (bits == 0) {
+            total = input[in];
+            in++;
+            bits += 8;
+        }
+        bits -= SPX_WOTS_LOGW;
+        output[out] = (total >> bits) & (SPX_WOTS_W - 1);
+        out++;
+    }
+}
+
+/* Computes the WOTS+ checksum over a message (in base_w). */
+static void wots_checksum(unsigned int *csum_base_w,
+                          const unsigned int *msg_base_w)
+{
+    unsigned int csum = 0;
+    unsigned char csum_bytes[(SPX_WOTS_LEN2 * SPX_WOTS_LOGW + 7) / 8];
+    unsigned int i;
+
+    /* Compute checksum. */
+    for (i = 0; i < SPX_WOTS_LEN1; i++) {
+        csum += SPX_WOTS_W - 1 - msg_base_w[i];
+    }
+
+    /* Convert checksum to base_w. */
+    /* Make sure expected empty zero bits are the least significant bits. */
+    csum = csum << ((8 - ((SPX_WOTS_LEN2 * SPX_WOTS_LOGW) % 8)) % 8);
+    ull_to_bytes(csum_bytes, sizeof(csum_bytes), csum);
+    base_w(csum_base_w, SPX_WOTS_LEN2, csum_bytes);
+}
+
+/* Takes a message and derives the matching chain lengths. */
+void chain_lengths(unsigned int *lengths, const unsigned char *msg)
+{
+    base_w(lengths, SPX_WOTS_LEN1, msg);
+    wots_checksum(lengths + SPX_WOTS_LEN1, lengths);
+}
+
+/**
+ * Takes a WOTS signature and an n-byte message, computes a WOTS public key.
+ *
+ * Writes the computed public key to 'pk'.
+ */
+void wots_pk_from_sig(unsigned char *pk,
+                      const unsigned char *sig, const unsigned char *msg,
+                      const spx_ctx *ctx, uint32_t addr[8])
+{
+    unsigned int lengths[SPX_WOTS_LEN];
+    uint32_t i;
+
+    chain_lengths(lengths, msg);
+
+    for (i = 0; i < SPX_WOTS_LEN; i++) {
+        set_chain_addr(addr, i);
+        gen_chain(pk + i*SPX_N, sig + i*SPX_N,
+                  lengths[i], SPX_WOTS_W - 1 - lengths[i], ctx, addr);
+    }
+}