From 7432d83676c2d9fde390932f72d3847764fcc116 Mon Sep 17 00:00:00 2001
From: Rhys Weatherley <rhys.weatherley@gmail.com>
Date: Thu, 2 Apr 2015 06:37:52 +1000
Subject: [PATCH] Wait for entropy pool to fill and autosave in TestRNG example

---
 libraries/Crypto/examples/TestRNG/TestRNG.ino | 5 ++++-
 1 file changed, 4 insertions(+), 1 deletion(-)

diff --git a/libraries/Crypto/examples/TestRNG/TestRNG.ino b/libraries/Crypto/examples/TestRNG/TestRNG.ino
index 7686cb7a..2304a5a0 100644
--- a/libraries/Crypto/examples/TestRNG/TestRNG.ino
+++ b/libraries/Crypto/examples/TestRNG/TestRNG.ino
@@ -21,6 +21,7 @@ TransistorNoiseSource noise(A1);
 bool calibrating = false;
 byte data[32];
 unsigned long startTime;
+size_t length = 48; // First block should wait for the pool to fill up.
 
 void setup() {
     Serial.begin(9600);
@@ -65,8 +66,10 @@ void loop() {
     RNG.loop();
 
     // Generate output whenever 32 bytes of entropy have been accumulated.
-    if (RNG.available(sizeof(data))) {
+    // The first time through, we wait for 48 bytes for a full entropy pool.
+    if (RNG.available(length)) {
         RNG.rand(data, sizeof(data));
         printHex(data, sizeof(data));
+        length = 32;
     }
 }