CyclicRedundancyCheck.py

#!/usr/bin/env python
# coding: utf-8

# In[47]:


def divisionEx_OR(divisor,dividend):
    divisor_len=len(divisor)
    temp_remind=dividend[:divisor_len]
    
    while(True):#performing devision using Ex-OR operation.....
        temp=''
        for i in range(divisor_len):  #Ex-OR operation
            if divisor[i]=='0' and temp_remind[i]=='0':
                temp+='0'
            elif divisor[i]=='1' and temp_remind[i]=='1':
                temp+='0'
            else:
                temp+='1'
 
        while(temp):  #removing 0's from starting of the reminder
            if temp[0]=='0':    
                temp=temp[1:]
            else:
                break

        if (len(dividend)+ len(temp) >=divisor_len):
            while(len(temp)<divisor_len): #for adding 0/1's from dividend to temp_reminder
                temp+=dividend[0]
                dividend=dividend[1:]
        else:
            reminder=temp
            break
        temp_remind=temp
    return reminder


# In[48]:


import numpy as np

parity_gen=input("Enter the parity generato binar code ")
mess=input("Enter the message for sending to reciever ")

for i in range(len(parity_gen)-1):
    mess+='0'
print("message after padding 0's before appliying CRC ",mess)

#changing var_names......
divisor=parity_gen;  dividend=mess;

reminder=divisionEx_OR(divisor,dividend)
print("reminder after division (in the sender side)",reminder)


# In[49]:


#for replacing 0's by reminder that are added before applying CRC
mess=mess[:len(mess)-len(reminder)]+reminder
print("message, after replacing 0's by reminder that are added before applying CRC, is",mess)


# In[50]:


#reciever side CRC
reminder_new=divisionEx_OR(divisor,mess)
print("reminder after division (in reciever side)",reminder_new)
if sum(int(x) for x in reminder_new)==0:
    print("There is no any error.")
else:
    print("There is some error.")


# In[52]:


#error
11001
1010101010

#no any error
10011
1101011111