How long should a TLS handshake take?

What is problem with TLS handshake?

I am trying to get a response from my backend via web using python requests.

I am passing username and password in the headers. But it does not work, the server is responding with the error TLS handshake failed with the following message.

Tlsv1 alert protocolversion. Also I can't find the reason for that message. Is there any limitation in TLS? I have done the same with Postman () and it works fine. I have tested the same thing in another computer and it works fine too.

I have tested some posts on stack overflow and it also works fine but it seems like I am missing something in my code. This is my code. Import requests. Token = "xoxp." username = "root". Password = "12345678". Response = requests.post("", headers=, auth=(username,password)) print(response). I was having the same problem with you, which may not be related but was similar. The python requests library is working fine, the problem is that the server does not allow TLS v1. So you will need to update your server to support the newer version of TLS.

See this answer for details.

How long should a TLS handshake take?

The TLS handshake is a standardized protocol for the exchange of security keys and some other necessary data.

It consists of a few messages, which are sent in a specific order: The client sends a ClientHello message to the server, which contains the list of supported cipher suites. The server responds with a ServerHello message, which contains the same list. At this point, both sides will have agreed on which cipher suites are available. Both messages are followed by one or more ChangeCipherSpec messages, which specify the preferred cipher suite for the next connection. This continues until a Finished message is received. This will happen only after both parties have exchanged all necessary information, and have agreed on a master secret key (the session key). This message closes the connection.

The TLS handshake is initiated by the client, and the server responds by sending a ClientHello message. This is followed by the ClientKeyExchange message, which includes the Diffie-Hellman exchange key. Next, we have the ChangeCipherSpec message, which specifies the preferred cipher suite for the next connection. This will happen only after both parties have exchanged all necessary information, and have agreed on a master secret key (the session key).

To determine how long the handshake should take, we need to determine how much data must be sent in each message. The number of bytes that need to be sent is given by: This is the sum of the sizes of the following types of messages: As a result, we get the following equation for the time taken: The client sends a ClientHello message containing 1024 bytes (512 bytes for the server, 512 bytes for the client). This is followed by the ServerHello message, which contains the same amount of data. At this point, both sides have agreed on which cipher suites are available. This will happen only after both parties have exchanged all necessary information, and have agreed on a master secret key (the session key).

This is the result of the math.

How can I speed up my TLS handshake?

I'd like to speed up the handshake phase of an TLS connection by as much as possible.

One idea I had is to use the handshake function and specify it as a function.

However, from reading RFC 5246, it seems to be impossible to achieve a significant speedup. What is the recommended way to do this? Note: Please explain the best, most generic way possible. The way you do it is a lot more efficient than a way I've never heard of.

Here are some approaches, but please note that I'm not really a TLS expert. 1) use your own version of the algorithm. If you've got crypto at your disposal, then it's totally trivial to implement your own version of TLS - maybe even one that allows multiple connections/handshakes per process, or uses ephemeral keys, or whatever. It might even run faster than standard TLS! The important thing is that you should be able to understand and predict the sequence of messages in a TLS handshake and thus implement them. The crypto should be at least as easy to understand as the standard TLS.

2) use standard library TLS implementation. If you don't have crypto, and just want to use standard tools, take a look at the OpenSSL command line tools.somesite.

However, the important thing is that your client will be running on top of an OpenSSL library. So when you've implemented a new TLS handshake algorithm, you can just re-write OpenSSL's code to perform the handshake. There are plenty of tutorials on the net about how to re-write OpenSSL.

If you're worried about breaking compatibility, you can use your own library with calls to the standard library functions - after all, you're just calling the functions from the standard library.