[Must Read] V3 Project Plan & Features

[ayushsharma82]

Hello everyone!

It has been 3 years since I created this library and it has received unprecedented love from the open-source community which has been the driving force to keep enhancing this library.

Today marks as a stepping stone for V3 of ElegantOTA which will further reduce the size of webpage, add exciting new features, potential bug fixes with new optimized source code and most importantly support for new microcontrollers.

To make this possible, I'll need your help in figuring out what's best and what you guys need in ElegantOTA. So comment down any feature you feel is missing in ElegantOTA and I'll add it in my project plan.

Supporting New Platforms:
For past 3 years ElegantOTA has been stuck with ESP32 and ESP8266 but now I wish to increase the coverage of ElegantOTA so that more people can make use of it to update their microcontroller conveniently. If you know or work with any microcontroller ( other than ESP32 or ESP8266 ) that has OTA capability please write it down in the comments below. I'll look into it.

The microcontroller doesn't necessarily needs to have in-built WiFi, it can also be a NCP ( Network Co-Processor ) architecture like Nano 33 IoT.

[vortigont]

Hey, @ayushsharma82,
How about the compressed updates support? For esp8266 it's pretty easy out of the box since it's supported by eboot code, just need to add file format detection.
For esp32 you need some additional code to decompress an upload on the fly.
Not so long ago I've made a small lib implementing zlib-compressed OTA uploads for ESP32.
Should be pretty easy to adopt your project to use esp32-flashz. Let me know if you like the idea, I may come up with PoC PR or something.
Cheers!

[ayushsharma82]

@vortigont Good Idea! That will be much appreciated and it will also ensure quick uploads for those who are experiencing upload issues due to signal loss.

[silverfisk]

I'd like to be able to upload cryptographic keys at the first installation.
I don't have an exact workflow how this could be done, but on a conceptual level both encryption and signing would be nice.

Before uploading a new OTA file, the certificate has been deployed to the device as part of the initial installation.

ElegantOTA then require a file encrypted and/or signed with the private file. The device then cannot be updated without having access to the private certificate file.

[ayushsharma82]

@silverfisk That will be a nice addition as well.

We can use an approach with AES128-CBC or AES256-CBC encryption where we have a logic to buffer incoming chunks from the HTTP server and pass the buffer with correct length for decryption on-the-fly. As with CBC based encryption we already know the block size, we will be able to decrypt the file as we receive it from the user.

I'm only concerned about the performance drawback which will be incurred due to decryption, I hope it doesn't deter the HTTP upload process.

Very nice overall suggestions from the community! Love it.

[ayushsharma82]

If anybody knows a public key cipher which can work with parallel computing ( decrypting ), then please do let us know. I really prefer public key cryptography in IoT.

Till then, I only see AES to work as it's successfully implemented on the hardware level and in SDK.

[vortigont]

asymmetric crypto is veeery slow, so it is used only for key exchange for symmetric ciphers.
i.e. it makes no sense to encrypt/decrypt the firmware during upload and flashing. Only to sign the update and provide keys and certs.

[silverfisk]

@vortigont how slow are we talking?

At least signing would be nice to validate the binary. But if it's too slow to decrypt perhaps it's better to use HTTPS to encapsulate the payload in symmetric encryption?
The binary will still contain the WiFi password and be treated as a secret though.

[vortigont]

@silverfisk the difference is huge, 3-5 orders of magnitude or so
AES

openssl speed aes-128-cbc
...
The 'numbers' are in 1000s of bytes per second processed.
type             16 bytes     64 bytes    256 bytes   1024 bytes   8192 bytes  16384 bytes
aes-128-cbc    1724778.47k  2039762.90k  2088857.86k  2083973.46k  2101630.29k  2093569.37k

RSA

openssl speed rsa2048
CPUINFO: OPENSSL_ia32cap=0x7ffaf3bfffebffff:0x18c05fdef3bfa7eb 
                                sign    verify    sign/s verify/s
rsa 2048 bits 0.000239s 0.000015s   4183.0  68721.9

actually I do not know any real life use case for asymmetric crypto other than KEX or signatures.

HTTPS for fw transfer is definitely right approach to secure the transfer itself. Other than this Espressif has all the required features for signed fw in their SDK, no need to reinvent the wheel. I'm not that deep into this area, mostly use open source firmware's for my needs :)

[ayushsharma82]

@vortigont Nice info regarding ciphers. Let's see if we can get at least the firmware signing integrated. Espressif does provide features like SecureBoot V2 and encryption but for ESP32 only. I'm going to make this library supported on other platforms as well so it will be a very important feature to have.

[vortigont]

@ayushsharma82
it's going to be a real pain to fit different arch'es into one lib, especially with things like encryption, lib dependencies, etc... You might wanna think twice about the design before stepping that sloppy road :) Might worth splitting the project into separate front-end/back-end parts. Well, anyway it's just a plans, isn't it? :)))

As for compression, I've done some dirty sketching and your front-end works pretty well with my flashz lib. Although there are some gaps that needs to be considered. Maybe open a discussion thread for this?

[ayushsharma82]

@vortigont You are pretty fast :)) I'll open a discussion thread. I did some renovations in past few days which switched the webpage from ancient 'Vuejs 2' to SvelteJS framework ( 73%~ size reduction - 54KB ( old ) to 15KB ( new ) ) and changed C++ library structure.

Do you want to wait for the changes to be live in a v3 branch? Or you can integrate it in the current version and I'll port it to V3 for you. ( whichever way you prefer )

Here's a sneak peak: