How much will it cost to consult a debugging?
I do not want to remove all the bugs, I just want to remove one bug.
Not even solution, but I just want to know the reason of the bug.
It will not be a hard problem for you.

I am working on a tls project and having some difficulties.
I asked a lot here, and had much help from you.
I tried for some time and concluded to consult you if the cost is not too much.

Github page of my project is https://github.com/ParkSeungwon/http2.
You should use the tls branch not the master branch.

you should install these libraries.
mysqlcppconn, jsoncpp, gmp(gnu multiprecision library), gmpxx(gmp for c++), catch2

On a linux machine, you can compile my project just by using make command on a root directory.
Just delete incltouch line in the root Makefile.

When compile is done, run ./https.x.(a tls server program) and run openssl s_client.
Then openssl will send bad record mac(20) alert.(after server finished message)
I want to know why this is happening.
I think you need to see tls.h, tls.cc, https.h and https.cc in tls directory.
Especially encode function of tls/tls.cc.

My program works fine with my own client. tls-cl.x. But not with openssl or wolfssl.
I post two pics to help you understand my problem.
First picture shows my https.x receiving bad record mac from openssl s_client.
But in server side the mac is verified well as you can see.
It decrypted the alert message well and MAC was also verified.
But client side, it says bad record mac..

The second picture shows that error is occured during decryption.
This is wolfssl example client. I added some logging lines to debug my program.
But all I added was just printf syntaxes.
From upper picture I could see that finished message content is well generated.(prf result 12)
I could verify it with prf result of my server.
Also hmac key was fine. But the hmac jumped some other lines I don't know about.
Because Hmac_update is not called. I added logging lines to every functions in hmac.c.

resuming....

Though I got an answer about this sequence number.
https://crypto.stackexchange.com/questi … -generated
Is this right?

I have another question.
https://stackoverflow.com/questions/525 … ke-message
This is about encrypted handshake message.

Yes, I am currently thinking about cousulting formally.
But I will try by myself for some more time because I am now travelling.

Thanks for making such a good functioned, well documented and easy to understand library.
And making it a GPL license.
My framework is also GPL. It maybe clumsy and simple. I think it has good ideas.
If you have time, please visit my github site http2-tls branch.
If you are willing to see my program and find out what's wrong it will be a great honor to me.
It wouldn't take long for a specialists like wolfssl programmers.

Thanks for attention.
I am using wolfssl library as crypt base.
And implementing basic TLS library of my own.
Is this a delicate infomation?
I thought it was an open infomation.
It is very hard to find well described document.
Even RFC5246 does not say a thing about this and some other details.
Could you kindly explain how to count the sequence number?

Thank you very much.
It did work.
Thank you again.
May I ask some general informations about TLS here?