merkeltree

• example1
• example2

References

• merkeltreePDF
• merketreePPT
• merkeltree1

toy merkel tree with demo, for fun and learning

DEMO

• There are two files, client.py and server.py

• Open two terminals and run both of the above mentioned files in each one like so.

  ./client.py <clientfile> AND ./server.py <serverfile>

• If the two files namely, clientfile.txt and serverfile.txt are exactly the same then the server would reply with a consistent reponse

• If not, then the server would respond with an inconsistent reponse and close connection.

• (UNDER CONSTRUCTION) Server sends back the changed chunks only to the client so the client can reconstruct with the ground truth file (ie. the serverfile)

V0

• Support for individual files only. Checks integrity of file.

• IMPLEMENTING ONLY A CLIENT SERVER MODEL, LATER P2P.

• HOW IT WORKS?

STEP 1. Client requests the hash of a file, expecting it to match with the current hash that it has access to of that same file. STEP 2. Client checks if the two match, if yes, then we are done and know that file hasn't changed on server. else we report error (saying that the file was changed) STEP 3: Client doesn't report error right away as in STEP 2. It requests further hashes down to the leaf nodes of merkel tree to find out which chunk(s) of data were changed. STEP 4: Then it requests for those chunks only. On receiving the server recalculates the root hash.

SOME NOTES

• The hashes are stored in the Merkle Tree. They are sent to the client on request.

• There are two file, clientfile.txt and serverfile.txt. These represent the the files the client and server has access to respectively. We are trying to simulate client and server on two different computers that are communicating for the file serverfile.txt( this is the most up to date file, and all clients must have this version to stay up to date).