1 files changed, 80 insertions, 0 deletions
diff --git a/reset-controller/fw/src/crypto.c b/reset-controller/fw/src/crypto.c
new file mode 100644
index 0000000..f4f79a4
--- /dev/null
+++ b/reset-controller/fw/src/crypto.c
@@ -0,0 +1,80 @@
+
+#include <assert.h>
+#include <unistd.h>
+#include <stdbool.h>
+#include <stdlib.h>
+#include <string.h>
+
+#include <sodium.h>
+
+#include "crypto.h"
+#include "simulation.h"
+
+
+void debug_hexdump(const char *name, const uint8_t *buf, size_t len);
+int verify_trigger_dom(const uint8_t inkey[PRESIG_MSG_LEN],
+        const char *domain_string, const uint8_t refkey[PRESIG_MSG_LEN]);
+
+
+void debug_hexdump(const char *name, const uint8_t *buf, size_t len) {
+    DEBUG_PRINTN("%20s: ", name);
+    for (size_t i=0; i<len;) {
+        for (size_t j=0; j<8 && i<len; i++, j++)
+            DEBUG_PRINTN("%02x ", buf[i]);
+        DEBUG_PRINTN(" ");
+    }
+    DEBUG_PRINTN("\n");
+}
+
+/* Returns trigger sig height for correct trigger */
+int verify_trigger_dom(const uint8_t inkey[PRESIG_MSG_LEN],
+        const char *domain_string, const uint8_t refkey[PRESIG_MSG_LEN]) {
+    uint8_t key[crypto_auth_hmacsha512_KEYBYTES];
+    uint8_t key_out[crypto_auth_hmacsha512_BYTES];
+
+    static_assert(PRESIG_MSG_LEN <= crypto_auth_hmacsha512_KEYBYTES);
+    memcpy(key, inkey, PRESIG_MSG_LEN);
+    memset(key + PRESIG_MSG_LEN, 0, sizeof(key) - PRESIG_MSG_LEN);
+    DEBUG_PRINT("ds \"%s\"", domain_string);
+    debug_hexdump("ref", refkey, PRESIG_MSG_LEN);
+
+    for (int i=0; i<presig_height; i++) {
+        DEBUG_PRINT("Verifying height rel %d abs %d", i, presig_height-i);
+        debug_hexdump("key", key, sizeof(key));
+        (void)crypto_auth_hmacsha512(key_out, (uint8_t *)domain_string, strlen(domain_string), key);
+        debug_hexdump("out", key_out, sizeof(key_out));
+        memcpy(key, key_out, PRESIG_MSG_LEN);
+        memset(key + PRESIG_MSG_LEN, 0, sizeof(key) - PRESIG_MSG_LEN);
+        
+        if (!memcmp(key, refkey, PRESIG_MSG_LEN))
+            return presig_height-i;
+    }
+
+    return 0;
+}
+
+int verify_trigger(const uint8_t inkey[PRESIG_MSG_LEN], int *height_out, int *domain_out) {
+    int res;
+    for (int i=0; i<_TRIGGER_DOMAIN_COUNT; i++) {
+        DEBUG_PRINT("Verifying domain %d", i);
+        if ((res = verify_trigger_dom(inkey, presig_domain_strings[i], presig_keys[i]))) {
+            DEBUG_PRINT("Match!");
+            if (height_out)
+                *height_out = res - 1;
+            if (domain_out)
+                *domain_out = i;
+            return 1;
+        }
+    }
+    return 0;
+}
+
+int oob_message_received(uint8_t msg[static OOB_TRIGGER_LEN]) {
+    int height, domain;
+    if (verify_trigger(msg, &height, &domain)) {
+        oob_trigger_activated(domain, height);
+        return 1;
+    }
+
+    return 0;
+}