Swapped out crypto engine for one that also works with AES-256

arch/rp2040/rp2040.ini

@@ -21,4 +21,4 @@ lib_deps =
   ${arduino_base.lib_deps}
   ${environmental_base.lib_deps}
   jgromes/RadioLib@^6.1.0
-  https://github.com/kokke/tiny-AES-c.git#f06ac37fc31dfdaca2e0d9bec83f90d5663c319b
+  rweather/Crypto

src/platform/rp2040/rp2040CryptoEngine.cpp

@@ -1,33 +1,63 @@
+#include "AES.h"
+#include "CTR.h"
 #include "CryptoEngine.h"
-#include "aes.hpp"
 #include "configuration.h"
 
 class RP2040CryptoEngine : public CryptoEngine
 {
+
+    CTRCommon *ctr = NULL;
+
   public:
     RP2040CryptoEngine() {}
 
     ~RP2040CryptoEngine() {}
 
+    virtual void setKey(const CryptoKey &k) override
+    {
+        CryptoEngine::setKey(k);
+        LOG_DEBUG("Installing AES%d key!\n", key.length * 8);
+        if (ctr) {
+            delete ctr;
+            ctr = NULL;
+        }
+        if (key.length != 0) {
+            if (key.length == 16)
+                ctr = new CTR<AES128>();
+            else
+                ctr = new CTR<AES256>();
+
+            ctr->setKey(key.bytes, key.length);
+        }
+    }
     /**
      * Encrypt a packet
      *
      * @param bytes is updated in place
      */
-    virtual void encrypt(uint32_t fromNode, uint64_t packetNum, size_t numBytes, uint8_t *bytes) override
+    virtual void encrypt(uint32_t fromNode, uint64_t packetId, size_t numBytes, uint8_t *bytes) override
     {
         if (key.length > 0) {
-            AES_ctx ctx;
-            initNonce(fromNode, packetNum);
-            AES_init_ctx_iv(&ctx, key.bytes, nonce);
-            AES_CTR_xcrypt_buffer(&ctx, bytes, numBytes);
+            initNonce(fromNode, packetId);
+            if (numBytes <= MAX_BLOCKSIZE) {
+                static uint8_t scratch[MAX_BLOCKSIZE];
+                memcpy(scratch, bytes, numBytes);
+                memset(scratch + numBytes, 0,
+                       sizeof(scratch) - numBytes); // Fill rest of buffer with zero (in case cypher looks at it)
+
+                ctr->setIV(nonce, sizeof(nonce));
+                ctr->setCounterSize(4);
+                ctr->encrypt(bytes, scratch, numBytes);
+            } else {
+                LOG_ERROR("Packet too large for crypto engine: %d. noop encryption!\n", numBytes);
+            }
         }
     }
 
-    virtual void decrypt(uint32_t fromNode, uint64_t packetNum, size_t numBytes, uint8_t *bytes) override
+    virtual void decrypt(uint32_t fromNode, uint64_t packetId, size_t numBytes, uint8_t *bytes) override
     {
         // For CTR, the implementation is the same
-        encrypt(fromNode, packetNum, numBytes, bytes);
+        encrypt(fromNode, packetId, numBytes, bytes);
     }
 
   private:

variants/rak11310/variant.h

@@ -4,13 +4,6 @@
 
 #define ARDUINO_ARCH_AVR
 
-#undef CBC
-#define CBC 0
-#undef CTR
-#define CTR 1
-#undef ECB
-#define ECB 0
-
 #define LED_CONN PIN_LED2
 #define LED_PIN LED_BUILTIN
 

variants/rpipico/variant.h

@@ -4,13 +4,6 @@
 
 #define ARDUINO_ARCH_AVR
 
-#undef CBC
-#define CBC 0
-#undef CTR
-#define CTR 1
-#undef ECB
-#define ECB 0
-
 #define USE_SH1106 1
 
 // default I2C pins:

variants/rpipicow/variant.h

@@ -4,13 +4,6 @@
 
 #define ARDUINO_ARCH_AVR
 
-#undef CBC
-#define CBC 0
-#undef CTR
-#define CTR 1
-#undef ECB
-#define ECB 0
-
 #define USE_SH1106 1
 
 // default I2C pins: