add encrypting for save files

add libhydrogen for encrypting and decrypting #9
2026-04-03 14:59:37 +02:00
parent abb6556fd4
commit c277ab10d9
68 changed files with 5737 additions and 74 deletions
@@ -0,0 +1,41 @@
+// Important: The SoftDevice *must* be activated to enable reading from the RNG
+// http://infocenter.nordicsemi.com/index.jsp?topic=%2Fcom.nordic.infocenter.nrf52832.ps.v1.1%2Frng.html
+
+#include <nrf_soc.h>
+
+static int
+hydro_random_init(void)
+{
+    const char       ctx[hydro_hash_CONTEXTBYTES] = { 'h', 'y', 'd', 'r', 'o', 'P', 'R', 'G' };
+    hydro_hash_state st;
+    const uint8_t    total_bytes     = 32;
+    uint8_t          remaining_bytes = total_bytes;
+    uint8_t          available_bytes;
+    uint8_t          rand_buffer[32];
+
+    hydro_hash_init(&st, ctx, NULL);
+
+    for (;;) {
+        if (sd_rand_application_bytes_available_get(&available_bytes) != NRF_SUCCESS) {
+            return -1;
+        }
+        if (available_bytes > 0) {
+            if (available_bytes > remaining_bytes) {
+                available_bytes = remaining_bytes;
+            }
+            if (sd_rand_application_vector_get(rand_buffer, available_bytes) != NRF_SUCCESS) {
+                return -1;
+            }
+            hydro_hash_update(&st, rand_buffer, available_bytes);
+            remaining_bytes -= available_bytes;
+        }
+        if (remaining_bytes <= 0) {
+            break;
+        }
+        delay(10);
+    }
+    hydro_hash_final(&st, hydro_random_context.state, sizeof hydro_random_context.state);
+    hydro_random_context.counter = ~LOAD64_LE(hydro_random_context.state);
+
+    return 0;
+}