Adding HMAC and nonce example

Author: RLeclair

examples/ECCX08HMAC/ECCX08HMAC.ino

@@ -0,0 +1,72 @@
+/*
+    ECCX08 HMAC functionality example
+
+    This sketch uses the ECC608 to generate an hmac on some data.
+    Stores key using nonce.
+
+    Used the Arduino Nano RP2040.
+
+    created 10 October 2022
+    by Raul Leclair
+*/
+
+#include <ArduinoECCX08.h>
+
+byte nonceKey[] = {
+    0x10, 0x10, 0x10, 0x10
+};
+byte data[] = {
+    0x10, 0x10, 0x10, 0x10, 0x10, 0x10, 0x10, 0x10,
+    0x10, 0x10, 0x10, 0x10, 0x10, 0x10, 0x10, 0x10,
+    0x10, 0x10, 0x10, 0x10, 0x10, 0x10, 0x10, 0x10,
+    0x10, 0x10, 0x10, 0x10, 0x10, 0x10, 0x10, 0x10,
+    0x10, 0x10, 0x10, 0x10, 0x10, 0x10, 0x10, 0x10,
+    0x10, 0x10, 0x10, 0x10, 0x10, 0x10, 0x10, 0x10,
+    0x10, 0x10, 0x10, 0x10, 0x10, 0x10, 0x10, 0x10
+};
+int dataLength = 56;
+
+void setup() {
+    Serial.begin(115200);
+    while (!Serial);
+
+    if (!ECCX08.begin()) {
+        Serial.println("Failed to initialize ECC608 board.");
+        while (1);
+    }
+
+    // Perform nonce
+    if (!ECCX08.nonce(nonceKey))
+    {
+        Serial.println("Failed to do nonce.");
+        while (1);
+    }
+
+    // Starting HMAC operation on tempkey slot
+    if (!ECCX08.beginHMAC(0xFFFF)) {
+        Serial.println("Failed to start HMAC operation.");
+        while (1);
+    }
+
+    if (!ECCX08.updateHMAC(data, dataLength)) {
+        Serial.println("Failed to update HMAC operation.");
+        while (1);
+    }
+
+    byte resultHMAC[32];
+    if (!ECCX08.endHMAC(resultHMAC)) {
+        Serial.println("Failed to end HMAC operation");
+        while (1);
+    }
+
+    Serial.println("HMAC Result: ");
+    for (int i = 0; i<sizeof(resultHMAC); i++) {
+        char hexChar[2];
+        sprintf(hexChar, "%02X", resultHMAC[i]);
+        Serial.print(hexChar);
+        Serial.print(" ");
+    }
+}
+
+void loop() {
+}