Scribd
Upload
17 views11 pages

Caesar Playfair

The document contains Python code implementations for two encryption techniques: the Caesar Cipher and the Playfair Cipher. The Caesar Cipher shifts characters in a string by a specified key, while the Playfair Cipher uses a 5x5 matrix to encrypt pairs of letters based on their positions. Both methods include functions for processing input strings, handling duplicates, and generating encrypted outputs.

Uploaded by

ratishra5824
Copyright
© © All Rights Reserved
We take content rights seriously. If you suspect this is your content, claim it here.
Available Formats
Download as DOCX, PDF, TXT or read online on Scribd
17 views11 pages

Caesar Playfair

The document contains Python code implementations for two encryption techniques: the Caesar Cipher and the Playfair Cipher. The Caesar Cipher shifts characters in a string by a specified key, while the Playfair Cipher uses a 5x5 matrix to encrypt pairs of letters based on their positions. Both methods include functions for processing input strings, handling duplicates, and generating encrypted outputs.

Uploaded by

ratishra5824
Copyright
© © All Rights Reserved
We take content rights seriously. If you suspect this is your content, claim it here.
Available Formats
Download as DOCX, PDF, TXT or read online on Scribd
You are on page 1/ 11

1.

Caeser Cipher:

CODE:
def caeser_cipher(string, key, mod=26):
ans = ""
for char in range(len(string)):

n = ord(string[char])

if n >= 65 and n <= 90:


n = (n - 65 + key) % mod + 65

elif n >= 97 and n <= 97 + 26 - 1:


n = (n - 97 + key) % mod + 97

string[char] = chr(n)

return ans.join(string)

string = list(input("Enter string: "))


key = int(input("Enter key: "))
# mod = int(input("Enter modulus number: "))
print("\nThe encoded string is: ")
print(caeser_cipher(string, key))

OUTPUT:
Playfair cipher:
CODE:
# Function to convert the string to lowercase

def toLowerCase(text):
return text.lower()

# Function to remove all spaces in a string

def removeSpaces(text):
newText = ""
for i in text:
if i == " ":
continue
else:
newText = newText + i
return newText

# Function to group 2 elements of a string


# as a list element

def Diagraph(text):
Diagraph = []
group = 0
for i in range(2, len(text), 2):
Diagraph.append(text[group:i])

group = i
Diagraph.append(text[group:])
return Diagraph

# Function to fill a letter in a string element


# If 2 letters in the same string matches

def FillerLetter(text):
k = len(text)
if k % 2 == 0:
for i in range(0, k, 2):
if text[i] == text[i + 1]:
new_word = text[0:i + 1] + str('x') + text[i + 1:]
new_word = FillerLetter(new_word)
break
else:
new_word = text
else:
for i in range(0, k - 1, 2):
if text[i] == text[i + 1]:
new_word = text[0:i + 1] + str('x') + text[i + 1:]
new_word = FillerLetter(new_word)
break
else:
new_word = text
return new_word

list1 = [
'a', 'b', 'c', 'd', 'e', 'f', 'g', 'h', 'i', 'k', 'l', 'm', 'n', 'o', 'p',
'q', 'r', 's', 't', 'u', 'v', 'w', 'x', 'y', 'z'
]

# Function to generate the 5x5 key square matrix


def generateKeyTable(word, list1):
key_letters = []
for i in word:
if i not in key_letters:
key_letters.append(i)

compElements = []
for i in key_letters:
if i not in compElements:
compElements.append(i)
for i in list1:
if i not in compElements:
compElements.append(i)

matrix = []
while compElements != []:
matrix.append(compElements[:5])
compElements = compElements[5:]

return matrix

def search(mat, element):


for i in range(5):
for j in range(5):
if (mat[i][j] == element):
return i, j

def encrypt_RowRule(matr, e1r, e1c, e2r, e2c):


char1 = ''
if e1c == 4:
char1 = matr[e1r][0]
else:
char1 = matr[e1r][e1c + 1]

char2 = ''
if e2c == 4:
char2 = matr[e2r][0]
else:
char2 = matr[e2r][e2c + 1]

return char1, char2

def encrypt_ColumnRule(matr, e1r, e1c, e2r, e2c):


char1 = ''
if e1r == 4:
char1 = matr[0][e1c]
else:
char1 = matr[e1r + 1][e1c]

char2 = ''
if e2r == 4:
char2 = matr[0][e2c]
else:
char2 = matr[e2r + 1][e2c]

return char1, char2

def encrypt_RectangleRule(matr, e1r, e1c, e2r, e2c):


char1 = ''
char1 = matr[e1r][e2c]

char2 = ''
char2 = matr[e2r][e1c]

return char1, char2

def encryptByPlayfairCipher(Matrix, plainList):


CipherText = []
for i in range(0, len(plainList)):
c1 = 0
c2 = 0
ele1_x, ele1_y = search(Matrix, plainList[i][0])
ele2_x, ele2_y = search(Matrix, plainList[i][1])

if ele1_x == ele2_x:
c1, c2 = encrypt_RowRule(Matrix, ele1_x, ele1_y, ele2_x, ele2_y)
# Get 2 letter cipherText
elif ele1_y == ele2_y:
c1, c2 = encrypt_ColumnRule(Matrix, ele1_x, ele1_y, ele2_x, ele2_y)
else:
c1, c2 = encrypt_RectangleRule(Matrix, ele1_x, ele1_y, ele2_x, ele2_y)

cipher = c1 + c2
CipherText.append(cipher)
return CipherText

# Python program to implement Playfair Cipher

# Function to convert the string to lowercase

def toLowerCase(text):
return text.lower()

# Function to remove all spaces in a string

def removeSpaces(text):
newText = ""
for i in text:
if i == " ":
continue
else:
newText = newText + i
return newText

# Function to group 2 elements of a string


# as a list element

def Diagraph(text):
Diagraph = []
group = 0
for i in range(2, len(text), 2):
Diagraph.append(text[group:i])

group = i
Diagraph.append(text[group:])
return Diagraph

# Function to fill a letter in a string element


# If 2 letters in the same string matches

def FillerLetter(text):
k = len(text)
if k % 2 == 0:
for i in range(0, k, 2):
if text[i] == text[i + 1]:
new_word = text[0:i + 1] + str('x') + text[i + 1:]
new_word = FillerLetter(new_word)
break
else:
new_word = text
else:
for i in range(0, k - 1, 2):
if text[i] == text[i + 1]:
new_word = text[0:i + 1] + str('x') + text[i + 1:]
new_word = FillerLetter(new_word)
break
else:
new_word = text
return new_word

list1 = [
'a', 'b', 'c', 'd', 'e', 'f', 'g', 'h', 'i', 'k', 'l', 'm', 'n', 'o', 'p',
'q', 'r', 's', 't', 'u', 'v', 'w', 'x', 'y', 'z'
]

# Function to generate the 5x5 key square matrix

def generateKeyTable(word, list1):


key_letters = []
for i in word:
if i not in key_letters:
key_letters.append(i)

compElements = []
for i in key_letters:
if i not in compElements:
compElements.append(i)
for i in list1:
if i not in compElements:
compElements.append(i)

matrix = []
while compElements != []:
matrix.append(compElements[:5])
compElements = compElements[5:]

return matrix

def search(mat, element):


for i in range(5):
for j in range(5):
if (mat[i][j] == element):
return i, j

def encrypt_RowRule(matr, e1r, e1c, e2r, e2c):


char1 = ''
if e1c == 4:
char1 = matr[e1r][0]
else:
char1 = matr[e1r][e1c + 1]

char2 = ''
if e2c == 4:
char2 = matr[e2r][0]
else:
char2 = matr[e2r][e2c + 1]
return char1, char2

def encrypt_ColumnRule(matr, e1r, e1c, e2r, e2c):


char1 = ''
if e1r == 4:
char1 = matr[0][e1c]
else:
char1 = matr[e1r + 1][e1c]

char2 = ''
if e2r == 4:
char2 = matr[0][e2c]
else:
char2 = matr[e2r + 1][e2c]

return char1, char2

def encrypt_RectangleRule(matr, e1r, e1c, e2r, e2c):


char1 = ''
char1 = matr[e1r][e2c]

char2 = ''
char2 = matr[e2r][e1c]

return char1, char2

def encryptByPlayfairCipher(Matrix, plainList):


CipherText = []
for i in range(0, len(plainList)):
c1 = 0
c2 = 0
ele1_x, ele1_y = search(Matrix, plainList[i][0])
ele2_x, ele2_y = search(Matrix, plainList[i][1])

if ele1_x == ele2_x:
c1, c2 = encrypt_RowRule(Matrix, ele1_x, ele1_y, ele2_x, ele2_y)
# Get 2 letter cipherText
elif ele1_y == ele2_y:
c1, c2 = encrypt_ColumnRule(Matrix, ele1_x, ele1_y, ele2_x, ele2_y)
else:
c1, c2 = encrypt_RectangleRule(Matrix, ele1_x, ele1_y, ele2_x, ele2_y)

cipher = c1 + c2
CipherText.append(cipher)
return CipherText

text_Plain = 'instruments'
text_Plain = removeSpaces(toLowerCase(text_Plain))
PlainTextList = Diagraph(FillerLetter(text_Plain))
if len(PlainTextList[-1]) != 2:
PlainTextList[-1] = PlainTextList[-1] + 'z'

key = "Monarchy"
print("Key text:", key)
key = toLowerCase(key)
Matrix = generateKeyTable(key, list1)

print("Plain Text:", text_Plain)


CipherList = encryptByPlayfairCipher(Matrix, PlainTextList)

CipherText = ""
for i in CipherList:
CipherText += i
print("CipherText:", CipherText)

OUTPUT:

You might also like