retrieve bearssl fingerprint

[or78rXxZ]

Basic Infos

• [ x] This issue complies with the issue POLICY doc.
• [ x] I have read the documentation at readthedocs and the issue is not addressed there.
• [ x] I have tested that the issue is present in current master branch (aka latest git).
• [ x] I have searched the issue tracker for a similar issue.
• If there is a stack dump, I have decoded it.
• I have filled out all fields below.

Platform

• Hardware: [Sonoff Dual R2]
• Core Version: [Release 2.6.0]
• Development Env: [Arduino IDE]
• Operating System: [Debian]

Settings in IDE

• Module: [Generic ESP8266 Module]
• Flash Mode: [dout]
• Flash Size: [1MB]
• lwip Variant: [v2 Lower Memory]
• Reset Method: [dtr]
• Flash Frequency: [40Mhz]
• CPU Frequency: [80Mhz]
• Upload Using: [SERIAL]
• Upload Speed: [115200)

Problem Description

In issue #6209 @earlephilhower said

I added some debugging info to the FP mismatch case, will do a PR later, but the problem is simply the FP doesn't match:
You could either use the BSSL calculated FP ...

I am working on converting my sketches from ax to bear. Is there a sketch available with tis extra debug info that will return the the bear calculated fingerprint? I specifically am trying to get the fingerprint for my mqtt server.

MCVE Sketch

#include <Arduino.h>

void setup() {

}

void loop() {

}

Debug Messages

Debug messages go here

[earlephilhower]

Just enable debugging for SSL and you get the dumps to serial. Or use OpenSSL or any other SSL utility and they can give the FPs as well.

Closing as a general question and not a core issue.