Crypto works!

src/esp32/ESP32CryptoEngine.cpp

@@ -0,0 +1,83 @@
+#include "CryptoEngine.h"
+#include "configuration.h"
+
+#include "crypto/includes.h"
+
+#include "crypto/common.h"
+
+// #include "esp_system.h"
+
+#include "crypto/aes.h"
+#include "crypto/aes_wrap.h"
+#include "mbedtls/aes.h"
+
+#define MAX_BLOCKSIZE 256
+
+class ESP32CryptoEngine : public CryptoEngine
+{
+
+    mbedtls_aes_context aes;
+
+    /// How many bytes in our key
+    uint8_t keySize = 0;
+
+  public:
+    ESP32CryptoEngine() { mbedtls_aes_init(&aes); }
+
+    ~ESP32CryptoEngine() { mbedtls_aes_free(&aes); }
+
+    /**
+     * Set the key used for encrypt, decrypt.
+     *
+     * As a special case: If all bytes are zero, we assume _no encryption_ and send all data in cleartext.
+     *
+     * @param numBytes must be 16 (AES128), 32 (AES256) or 0 (no crypt)
+     * @param bytes a _static_ buffer that will remain valid for the life of this crypto instance (i.e. this class will cache the
+     * provided pointer)
+     */
+    virtual void setKey(size_t numBytes, uint8_t *bytes)
+    {
+        keySize = numBytes;
+        DEBUG_MSG("Installing AES%d key!\n", numBytes * 8);
+        if (numBytes != 0) {
+            auto res = mbedtls_aes_setkey_enc(&aes, bytes, numBytes * 8);
+            assert(!res);
+        }
+    }
+
+    /**
+     * Encrypt a packet
+     *
+     * @param bytes is updated in place
+     */
+    virtual void encrypt(uint32_t fromNode, uint64_t packetNum, size_t numBytes, uint8_t *bytes)
+    {
+        if (keySize != 0) {
+            uint8_t stream_block[16];
+            static uint8_t scratch[MAX_BLOCKSIZE];
+            size_t nc_off = 0;
+
+            // DEBUG_MSG("ESP32 encrypt!\n");
+            initNonce(fromNode, packetNum);
+            assert(numBytes <= 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)
+
+            auto res = mbedtls_aes_crypt_ctr(&aes, numBytes, &nc_off, nonce, stream_block, scratch, bytes);
+            assert(!res);
+        }
+    }
+
+    virtual void decrypt(uint32_t fromNode, uint64_t packetNum, size_t numBytes, uint8_t *bytes)
+    {
+        // DEBUG_MSG("ESP32 decrypt!\n");
+
+        // For CTR, the implementation is the same
+        encrypt(fromNode, packetNum, numBytes, bytes);
+    }
+
+  private:
+};
+
+CryptoEngine *crypto = new ESP32CryptoEngine();