Put a bit of order in the src directory, group and name things appropriately

src/platform/nrf52/NRF52CryptoEngine.cpp

@@ -0,0 +1,49 @@
+#include "configuration.h"
+#include "CryptoEngine.h"
+#include <Adafruit_nRFCrypto.h>
+#include "aes-256/tiny-aes.h"
+class NRF52CryptoEngine : public CryptoEngine
+{
+  public:
+    NRF52CryptoEngine() {}
+
+    ~NRF52CryptoEngine() {}
+
+    /**
+     * Encrypt a packet
+     *
+     * @param bytes is updated in place
+     */
+    virtual void encrypt(uint32_t fromNode, uint64_t packetId, size_t numBytes, uint8_t *bytes) override
+    {
+        if (key.length > 16) {
+            DEBUG_MSG("Software encrypt fr=%x, num=%x, numBytes=%d!\n", fromNode, (uint32_t) packetId, numBytes);
+            AES_ctx ctx;
+            initNonce(fromNode, packetId);
+            AES_init_ctx_iv(&ctx, key.bytes, nonce);
+            AES_CTR_xcrypt_buffer(&ctx, bytes, numBytes);
+        } else if (key.length > 0) {
+            DEBUG_MSG("nRF52 encrypt fr=%x, num=%x, numBytes=%d!\n", fromNode, (uint32_t) packetId, numBytes);
+            nRFCrypto.begin();
+            nRFCrypto_AES ctx;
+            uint8_t myLen = ctx.blockLen(numBytes);
+            char encBuf[myLen] = {0};
+            initNonce(fromNode, packetId);
+            ctx.begin();
+            ctx.Process((char*)bytes, numBytes, nonce, key.bytes, key.length, encBuf, ctx.encryptFlag, ctx.ctrMode);
+            ctx.end();
+            nRFCrypto.end();
+            memcpy(bytes, encBuf, numBytes);
+        }
+    }
+
+    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, packetId, numBytes, bytes);
+    }
+
+  private:
+};
+
+CryptoEngine *crypto = new NRF52CryptoEngine();