From 6f2e1658f86672b42f7cf1411f5a02d269ab39fb Mon Sep 17 00:00:00 2001
From: Mark C <mc@blaidd.cymru>
Date: Mon, 28 May 2018 14:03:50 +0100
Subject: [PATCH 1/3] changed random() to getRSSI() and added a function to get
 a better random byte. --M.

---
 src/LoRa.cpp | 21 ++++++++++++++++++++-
 src/LoRa.h   |  1 +
 2 files changed, 21 insertions(+), 1 deletion(-)

diff --git a/src/LoRa.cpp b/src/LoRa.cpp
index 4296e76..163e3c4 100644
--- a/src/LoRa.cpp
+++ b/src/LoRa.cpp
@@ -512,9 +512,28 @@ void LoRaClass::disableCrc()
   writeRegister(REG_MODEM_CONFIG_2, readRegister(REG_MODEM_CONFIG_2) & 0xfb);
 }
 
+byte LoRaClass::getRSSI()
+{
+    return readRegister(REG_RSSI_WIDEBAND);
+}
+
 byte LoRaClass::random()
 {
-  return readRegister(REG_RSSI_WIDEBAND);
+  int n=0, bits=7;
+  while(bits--) {
+    n<<=1;
+    while(1){
+      // implement a basic von Neumann Extractor
+      int a=(readRegister(REG_RSSI_WIDEBAND) & 1);
+      if(a != (readRegister(REG_RSSI_WIDEBAND) & 1)){
+        // put random, whitened bit in n
+        n |= a;
+        break;
+      }
+    }
+  }
+  // return the random byte
+  return n;
 }
 
 void LoRaClass::setPins(int ss, int reset, int dio0)
diff --git a/src/LoRa.h b/src/LoRa.h
index 248a988..0c4831b 100644
--- a/src/LoRa.h
+++ b/src/LoRa.h
@@ -71,6 +71,7 @@ class LoRaClass : public Stream {
   void crc() { enableCrc(); }
   void noCrc() { disableCrc(); }
 
+  byte getRSSI();
   byte random();
 
   void setPins(int ss = LORA_DEFAULT_SS_PIN, int reset = LORA_DEFAULT_RESET_PIN, int dio0 = LORA_DEFAULT_DIO0_PIN);

From ddbbbbf2c7d80c9b128c1e4e5bfda0da93e13355 Mon Sep 17 00:00:00 2001
From: Mark C <mc@blaidd.cymru>
Date: Mon, 28 May 2018 14:07:44 +0100
Subject: [PATCH 2/3] added documentation notes for previous commit.

---
 API.md | 12 +++++++++++-
 1 file changed, 11 insertions(+), 1 deletion(-)

diff --git a/API.md b/API.md
index a9a89b5..1775bf7 100644
--- a/API.md
+++ b/API.md
@@ -331,9 +331,19 @@ LoRa.disableCrc();
 
 ## Other functions
 
+### Get RSSI
+
+Gets the RSSI value from the radio. 
+
+```
+byte b = LoRa.getRSSI();
+```
+
+Returns RSSI value as a byte.
+
 ### Random
 
-Generate a random byte, based on the Wideband RSSI measurement.
+Generate a random byte, based on the Wideband RSSI measurement run through a von Neumann Extractor.
 
 ```
 byte b = LoRa.random();

From c34a7193548570df8bec6b92be7d4bb4f92d63b8 Mon Sep 17 00:00:00 2001
From: Mark C <mc@blaidd.cymru>
Date: Mon, 28 May 2018 14:15:11 +0100
Subject: [PATCH 3/3] Added required warning that the output of random() is not
 CS.

---
 API.md | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/API.md b/API.md
index 1775bf7..d1c230c 100644
--- a/API.md
+++ b/API.md
@@ -343,7 +343,7 @@ Returns RSSI value as a byte.
 
 ### Random
 
-Generate a random byte, based on the Wideband RSSI measurement run through a von Neumann Extractor.
+Generate a random byte, based on the Wideband RSSI measurement run through a von Neumann Extractor. **NB** - these are not cryptographically secure random numbers! Use with caution!
 
 ```
 byte b = LoRa.random();