The Third&Fourth Week

Hi there,

Here is results of past 2 weeks:

1. Trusted Peer improvements

There was some problems with TP's logic. The first - trusted peer was sending packets for checking which have been received from splitter. It's a such a useless activity, so now there is a check that a new packet not from splitter. Here is some code:

def process_next_message(self):
        chunk_number = Peer_DBS.process_next_message(self)
        if chunk_number > 0 and self.current_sender != self.splitter:
            if self.counter == 0:
                self.send_chunk_hash(chunk_number)
                self.counter = self.calculate_next_sampled()
            else:
                self.counter -= 1
        return chunk_number

def receive_the_next_message(self):
        message, sender = Peer_DBS.receive_the_next_message(self)
        self.current_sender = sender
        return message, sender

The method  process_next_message is calling method receive_the_next_message inside itself, which is overrided: it stores the sender in class variable.

The second one - 255 problem. TP sent every 255 packet. Now the next packet to send is choosed on random basis:

def calculate_next_sampled(self):
        max_random = len(self.peer_list) / TrustedPeer.SAMPLING_EFFORT
        return random.randint(1, max(1, max_random)) + TrustedPeer.PASS_NUMBER

Thanks to Juan Álvaro for idea.

2. Testing plan for STrPe mechanism

I have begun the Testing Plan for STrPe mechanism. I have described several types of attack and some network configurations in this document.

3. Benchmarks for crypto-libs

There are some preparations for STrPe-DS! I have performed some synthetic tests for PyCrypto lib and ecdsa lib. Both libraries can be installed via pip. Here is results (i7 2,9 GHz):

Exact results for pycrypto lib:

key.sign x10 times: 0.00385499000549s
key.verify x10 times: 0.00309109687805s

key.sign x100 times: 0.0352149009705s
key.verify x100 times: 0.0317900180817s

key.sign x1000 times: 0.332525968552s
key.verify x1000 times: 0.326780080795s 

Sources of benchmarks can be accessed here.

 

The updated commands to test STrPe-mechanism:

 $ cd /path/to/p2psp/src/  
 $ vlc Big_Buck_Bunny_small.ogv --sout "#duplicate{dst=standard{mux=ogg,dst=,access=http}}" &  
 $ xterm -e "./splitter.py --source_port 8080 --strpe "127.0.0.1:56000" &  
 $ xterm -e "./peer.py --use_localhost" &  
 $ vlc http://localhost:9999 &  
 $ xterm -e "./peer.py --use_localhost --player_port 10000 --trusted --port 56000" &  
 $ vlc http://localhost:10000 &  
 $ xterm -e "./peer.py --use_localhost --player_port 10001 --malicious" &  
 $ vlc http://localhost:10001 &  

Thanks!