Basic SSL

Compilation

In Sming the SSL support is not enabled by default.

In order to enable it you should compile your project with the ENABLE_SSL=1 directive:

make ENABLE_SSL=1

Now you can flash your application to your ESP8266 device.

Debug Information

If you want to see more debug information during compile type you should enable SSL_DEBUG, like this:

make ENABLE_SSL=1 SSL_DEBUG=1

Slow SSL negotiation

The initial SSL negotiation is CPU intensive. By default SmingFramework switches the CPU frequency from 80 to 160 MHz. After the negotiation the CPU is switched back to 80 MHz.

If your device is running on battery this can drain the battery much faster. If you do not want the switch from 80 to 160 MHz to happen then make sure to recompile SmingFramework with SSL_SLOW_CONNECT directive:

make USER_CFLAGS="SSL_SLOW_CONNECT=1"

Memory usage

SSL uses a significant amount of RAM. You can build this sample to track heap usage and output statistics every 5 seconds:

make ENABLE_MALLOC_COUNT=1

References

• Source Code

• Sming (main)

• malloc_count

SoC support

• esp32

• esp32c2

• esp32c3

• esp32s2

• esp32s3

• esp8266

• host

• rp2040

• rp2350