Simple Socket Client Project 1

Goals Write a simple TCP/IP client that supports a specific protocol The server is running right now on cs5700f17.ccs.neu.edu:27998 If your program is correct, the server will send you a secret flag Turn in your code and the secret flag in order to receive full credit DUE: January 19, 11:59:59 PM

Your Program Can be written in whatever language you want Must compile on the CCIS Linux machines and run on the command line Don’t use crazy libraries that aren’t installed by default Don’t write a program with a GUI If you use an IDE, make sure your code doesn’t have any hidden dependencies

Command Line Syntax $ ./client <-p port> <-s> [hostname] [NEU ID] Your client must follow this syntax exactly Hostname – the name of the server E.g. cs5700f17.ccs.neu.edu Port – Optional parameter, the port the server is listening on By default, port is 27998 Secure – Optional parameter, indicates that the client should use an SSL encrypted socket NEU ID – your NEU ID

The Protocol (Part 1) 4 messages Your client begins by sending HELLO HELLO, STATUS, SOLUTION, and BYE Your client begins by sending HELLO cs3700spring2018 HELLO [your NEU ID]\n The server will respond with a STATUS cs3700spring2018 STATUS [an equation]\n The equation will be a simple math problem E.g. “5 + 10” or “32 * 509” or “2391 / 93”

The Protocol (Part 2) Your client returns a SOLUTION message cs3700spring2018 [the solution]\n The server may respond with another STATUS, or it may respond with BYE cs3700spring2018 BYE [secret flag]\n The secret flag is what you want :)

Turning In Your Project Register your group You have to do this even for a group of 1! Create a directory for your files All of your (well documented) code Makefile README secret_flags (a file with the secret flags of the group members, one per line) Run the turn-in script

Grading 4% of your total grade To receive full credit: Turn in working code that compiles/runs successfully Turn in the secret flags of all group members If your code doesn’t compile or doesn’t run, you get zero credit All code will be scanned by plagiarism detection software

Common Issues “Do I need a Makefile if my code is in <some non-compiled scripting language>?” YES, but it can simply do things like set your script to be executable If running ‘make’ from your directory gives an error, you lose a point “I’m working from home and I cannot connect to the server!” Sadly, the university firewall blocks all traffic on non-standard ports You have two options: SSH into a CCIS machine and run your code from there Use the Northeastern VPN to bypass the firewall

Extra Credit Possible to get 0.5% extra credit (4.5% total) Augment your client to support SSL sockets The protocol is exactly the same, its just encrypted with SSL If your SSL client is successful, you will get another secret flag Put these new keys in the secret_flags file The SSL server is running on the same host, port 27999 Warning: Java’s SSL implementation is awful