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5_checksum_server.py
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5_checksum_server.py
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import socket
k = 8
# -------- Function to find the checksum of message --------
def findChecksum(msg, k):
# Dividing sent message in packets of k bits.
c1 = msg[ 0 : k]
c2 = msg[ k : 2 * k]
c3 = msg[2 * k : 3 * k]
c4 = msg[3 * k : 4 * k]
# Calculating the binary sum of packets
Sum = bin(int(c1, 2)+int(c2, 2)+int(c3, 2)+int(c4, 2))[2:]
# Adding the overflow bits
if(len(Sum) > k):
x = len(Sum)-k
Sum = bin(int(Sum[0:x], 2)+int(Sum[x:], 2))[2:]
if(len(Sum) < k):
Sum = '0'*(k-len(Sum))+Sum
# Calculating the complement of sum
Checksum = ''
for i in Sum:
if(i == '1'):
Checksum += '0'
else:
Checksum += '1'
return Checksum
# -------- Main Function --------
host = socket.gethostname()
port = 5000
server_socket = socket.socket()
server_socket.bind((host, port))
server_socket.listen(2)
conn, address = server_socket.accept()
print("Connection from: " + str(address))
data1 = conn.recv(1024).decode()
Checksum = findChecksum(data1, k)
print("Checksum from the connected user (client): " + Checksum)
msg = input("Enter receiver message to send: ")
conn.send(msg.encode())
conn.close()