playfair cipher python
key=input("Enter key")
key=key.replace(" ", "")
key=key.upper()
def matrix(x,y,initial):
return [[initial for i in range(x)] for j in range(y)]
result=list()
for c in key: #storing key
if c not in result:
if c=='J':
result.append('I')
else:
result.append(c)
flag=0
for i in range(65,91): #storing other character
if chr(i) not in result:
if i==73 and chr(74) not in result:
result.append("I")
flag=1
elif flag==0 and i==73 or i==74:
pass
else:
result.append(chr(i))
k=0
my_matrix=matrix(5,5,0) #initialize matrix
for i in range(0,5): #making matrix
for j in range(0,5):
my_matrix[i][j]=result[k]
k+=1
def locindex(c): #get location of each character
loc=list()
if c=='J':
c='I'
for i ,j in enumerate(my_matrix):
for k,l in enumerate(j):
if c==l:
loc.append(i)
loc.append(k)
return loc
def encrypt(): #Encryption
msg=str(input("ENTER MSG:"))
msg=msg.upper()
msg=msg.replace(" ", "")
i=0
for s in range(0,len(msg)+1,2):
if s<len(msg)-1:
if msg[s]==msg[s+1]:
msg=msg[:s+1]+'X'+msg[s+1:]
if len(msg)%2!=0:
msg=msg[:]+'X'
print("CIPHER TEXT:",end=' ')
while i<len(msg):
loc=list()
loc=locindex(msg[i])
loc1=list()
loc1=locindex(msg[i+1])
if loc[1]==loc1[1]:
print("{}{}".format(my_matrix[(loc[0]+1)%5][loc[1]],my_matrix[(loc1[0]+1)%5][loc1[1]]),end=' ')
elif loc[0]==loc1[0]:
print("{}{}".format(my_matrix[loc[0]][(loc[1]+1)%5],my_matrix[loc1[0]][(loc1[1]+1)%5]),end=' ')
else:
print("{}{}".format(my_matrix[loc[0]][loc1[1]],my_matrix[loc1[0]][loc[1]]),end=' ')
i=i+2
def decrypt(): #decryption
msg=str(input("ENTER CIPHER TEXT:"))
msg=msg.upper()
msg=msg.replace(" ", "")
print("PLAIN TEXT:",end=' ')
i=0
while i<len(msg):
loc=list()
loc=locindex(msg[i])
loc1=list()
loc1=locindex(msg[i+1])
if loc[1]==loc1[1]:
print("{}{}".format(my_matrix[(loc[0]-1)%5][loc[1]],my_matrix[(loc1[0]-1)%5][loc1[1]]),end=' ')
elif loc[0]==loc1[0]:
print("{}{}".format(my_matrix[loc[0]][(loc[1]-1)%5],my_matrix[loc1[0]][(loc1[1]-1)%5]),end=' ')
else:
print("{}{}".format(my_matrix[loc[0]][loc1[1]],my_matrix[loc1[0]][loc[1]]),end=' ')
i=i+2
while(1):
choice=int(input("n 1.Encryption n 2.Decryption: n 3.EXIT"))
if choice==1:
encrypt()
elif choice==2:
decrypt()
elif choice==3:
exit()
else:
print("Choose correct choice")