add sha256 impl

crypto.c

@@ -0,0 +1,37 @@
+/*
+ *  Wrapper for crypto implementation on device
+ *
+ * */
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+
+#include "util.h"
+#include "crypto.h"
+
+#ifdef USE_SOFTWARE_IMPLEMENTATION
+
+#include "sha256.h"
+
+static SHA256_CTX sha256_ctx;
+
+void crypto_sha256_init()
+{
+    sha256_init(&sha256_ctx);
+}
+
+
+void crypto_sha256_update(uint8_t * data, size_t len)
+{
+    sha256_update(&sha256_ctx, data, len);
+}
+
+
+void crypto_sha256_final(uint8_t * hash)
+{
+    sha256_final(&sha256_ctx, hash);
+}
+
+#else
+#error "No crypto implementation defined"
+#endif