I made this variation of a Caesar cipher. Any tips on improving, either method or underlying algorithm? Don't worry... I promise not to use it to encrypt anything of value.
#########################
# #
# caesarED By: 1 0 3 E #
# 0 3 E 1 #
# 3 E 1 0 #
# E 1 0 3 #
# #
#########################
#########################
import random
######
#@@@@@# StringDoc+InitCond
######
""" CeasarED: encryption, decryption and public & private keygen
----------------
Encryption:
----------------
P1 = plaintext,
bS = baseString
pKa = shuffAlphaPrivateKey
pK1=shuffNumPrivateKey
PKa = alphaPublic key
PK1 = numPubKey
k = shift factor
C1 = cipher1
C2 = cipher2
C3 = cipher3
NaCl= salt
1. P1 >>C1 -- to each letter in plaintext adds k*i
C1[i] = (P1[i]+bS[i*k]) % bS)
2.C1 >> C2 -- for each letter of cipher1 in baseString sub letter in alphaPrivateKey
C2[i] = pKa[bS[C1[i]]]
3.C2 >> C3 -- generate salt, add k to each num in numPubKey, use numPrivateKey to select salt from (numPubKey+k)
NaCl[i] = PKa[(pK1[i+k]) mod len (PKa) ]
C3[i] = bS[(C2[i] + NaCl[i]) mod len(bS)]
----------------
Decryption:
----------------
Reverse of encryption.
----------------
KeyGens:
----------------
PUBLIC
----------------
keyLen = length of public key
1. Generate OneKey
OneKey = keyLen length array of random integers range 0 to (len(baseString) -1)
2. Generate alphaKeySpace
alphaKeySpace[i] = baseString[OneKey[i]]
PRIVATE
----------------
1. Generate numPrivKey, for each char in baseString, find all pos of char in alphaKeySpace, record i[] , choose one i for each char
2. Generate alphaPrivKey
pKa[i] = baseString[pK1[i]]
3. Generate shuffAlphaPrivKey and shuffNumPrivKey, arrange elem in list alphaPriv Key in random order
"""
main = '' #begin main loop
######
#@@@@@# variStore
######
"""
Global key Variables
"""
baseString = list('abcdefghijklmnopqrstuvwxyz ABCDEFGHIJKLMNOPQRSTUVWXYZ1234567890,.!?;:%#+@')
alphaKeySpace=''
oneKey=[]
shuffOnePrivKey = [] # numVer Privkey
shuffAlphaPrivKey = '' #charVer PrivKey
listShuffAlphaPrivKey = list(shuffAlphaPrivKey)
kShuffOnePrivKey = [] # salt = alphaKeySpace[shuffOnePrivKey[i+k]]
k=int() #shiftVari
######
#@@@@@# functions
######
###
#@#ENCRYPTION
###
def encrypt():
"""
Ask to input plaintext then encrypts, also gen specific key varis from priv key pub key.
-- gen specific key varis
-- plaintext >> cipher1
-- cipher1 >> cipher 2
-- cipher2 >> cipher3
"""
plaintext = input('Enter message:\n>>')
kShuffAlphaPrivKey=''
listKShuffAlphaPrivKey=[]
cipher1=''
cipher2=''
cipher3=''
"""
GenKeyVaris from shuffOnePrivKey
"""
kShuffOnePrivKey = [((x + k)%len(baseString)) for x in shuffOnePrivKey] # gen kshuffoneprivkey
for i in kShuffOnePrivKey: #gen kShuffAlphaPrivKey using kShuffOnePrivKey to lookup alphaKeySpace
kShuffAlphaPrivKey += (alphaKeySpace[i])
listKShuffAlphaPrivKey = list(kShuffAlphaPrivKey)
"""
plaintext >> cipher1
-- To each letter in plaintext adds shiftfactor * i
"""
i = 0
for c in plaintext: # add k*i to each elem plaintext form cipher1
if c in baseString:
i += 1
cipher1 += baseString[(baseString.index((c))+(k*i))%(len(baseString))]
listCipher1 = list(cipher1)
"""
cipher1 >> cipher2
-- To each letter in listcipher1, subs with letter in same position in private key
"""
listCipher2=''
for i in listCipher1:
c = baseString.index(i)
cipher2 += shuffAlphaPrivKey[(baseString.index(i)%(len(baseString)))]
listCipher2 = list(cipher2)
"""
cipher2 >> cipher3
-- To each letter in listCipher2 adds letter value in k-shifted private key
"""
c=0
for i in listCipher2:
if c > (len(baseString)-1): # (c)mod(baseString)
c = 0
cipher3 += baseString[(baseString.index(i) + baseString.index(listKShuffAlphaPrivKey[c]))%(len(baseString))]
c +=1
"""
OUT
"""
print('Encrypted message is:\n' + cipher3)
###
#@#DECRYPTION
###
def decrypt():
"""
Ask to input ciphertext then decrypts, also gen specific key varis from priv key pub key.
-- gen specific key varis
-- cipher3 >> cipher2
-- cipher2 >> cipher1
-- cipher1 >> plaintextOne
"""
cipherThree = input('Enter ciphertext to decrypt:\n>>')
listCipherThree= list(cipherThree)
kShuffAlphaPrivKey=''
listKShuffAlphaPrivKey=[]
cipherOne=''
cipherTwo=''
plaintextOne=''
"""
GenKeyVaris from shuffOnePrivKey
"""
kShuffOnePrivKey = [((x + k)%len(baseString)) for x in shuffOnePrivKey] # gen kshuffoneprivkey
for i in kShuffOnePrivKey: #gen kShuffAlphaPrivKey using kShuffOnePrivKey to lookup alphaKeySpace
kShuffAlphaPrivKey += (alphaKeySpace[i])
listKShuffAlphaPrivKey = list(kShuffAlphaPrivKey)
listShuffAlphaPrivKey = list(shuffAlphaPrivKey)
"""
CipherThree >> cipherTwo
"""
c = 0
for i in cipherThree:
if c > (len(baseString)-1): # (c)mod(baseString)
c = 0
cipherTwo += baseString[(baseString.index(i) - baseString.index(listKShuffAlphaPrivKey[c]))%(len(baseString))]
c += 1
listCipherTwo= list(cipherTwo)
"""
cipherTwo >> cipherOne
"""
for i in listCipherTwo:
cipherOne += baseString[listShuffAlphaPrivKey.index(i)]
listCipherOne= list(cipherOne)
"""
cipherOne >> plaintextOne
"""
i = 0
for p in listCipherOne:
i += 1
plaintextOne += baseString[(baseString.index(p)-(k*i))%(len(baseString))]
"""
OUT
"""
print('Decrypted message is:\n' + plaintextOne)
###
#@#pubKeyGen
###
def pubKeyGen():
"""
pubKeyGen: generates n-length public key
"""
global alphaKeySpace
alphaKeySpace=''
check = 0
while check == 0:
keySize = int(input('Enter keySpace length ( keySpace > 1000 )\n>>'))
oneKey=[]
"""
Generate random string, element range 0-72, length = keyLength
"""
c=0
while keySize > c:
r1 = str(random.randint(0,72))
oneKey += r1 + ' '
c += 1
"""
Read oneKey between spaces and add entries converted
using dictionary to alphaKeySpace
"""
temp1 = ''
for i in oneKey:
if i == ' ':
alphaKeySpace += (baseString[int(temp1)]) # convert ints to letters, store in alphaKey
temp1= ''
if i != ' ':
temp1 += i # -w i to temp1 ie -r number
"""
Check keyspace contains all char
"""
for i in baseString:
if i not in alphaKeySpace:
print('INVALID keySpace')
check = 0
break
else:
check = 1
"""
OUT
"""
print('Your alphaKeySpace is:\n' + alphaKeySpace)
###
#@#privKeyGen
###
def privKeyGen( ):
"""
privKeyGen: generates 73 char private key
"""
baseString = list('abcdefghijklmnopqrstuvwxyz ABCDEFGHIJKLMNOPQRSTUVWXYZ1234567890,.!?;:%#+@')
pos = [] #position
sel = [] #selection
global shuffAlphaPrivKey
shuffAlphaPrivKey=''
global shuffOnePrivKey
shuffOnePrivKey=[]
"""
Fill pos with positions of each char in alphaKeySpace
"""
for i in baseString:
pos = [pos for pos, char in enumerate(alphaKeySpace) if char == i] #positions of character i in alphaKeySpace
sel.append(random.choice(pos)) #for each char add random pos to sel
shuffOnePrivKey = random.sample(sel,73) # list of pos chosen shuffled
"""
Trans chosen numbers to char
"""
for i in shuffOnePrivKey:
shuffAlphaPrivKey += (alphaKeySpace[i])
print('Your private key is:\n' + shuffAlphaPrivKey) # private key
###### ##
#@@@@@@@# mainLoop
########
while main == '':
print('\n','-'*39,'\n',' caesarED: encryption and decryption','\n','-'*39,'\n')
main = input('"e" to encrypt, "d" to decrypt, "c" for command list or "x" to exit\n>>')
######
#@@@@@# ENCRYPTION
######
while main == 'e': #encrypt
"""
Check pub & priv keySpace not empty
"""
if alphaKeySpace == '':
print('Generating public key...')
main ='g'
break
if shuffAlphaPrivKey == '':
print('Generating private key...')
main ='s'
break
if k == 0:
k = int(input('Enter Shift Factor:\n>>'))
"""
Encrypt
"""
encrypt()
main='' #reset loop
######
#@@@@@# DECRYPTION
######
if main == 'd': #decrypt
"""
Decrypt
"""
decrypt()
main = ''
######
#@@@@@# setShiftFactor
######
if main == 'k':
"""
Set shift factor 'k'
"""
k = int(input('Enter shift factor:\n>>'))
######
#@@@@@# keySpaceGen
######
if main == 'g':
"""
Generate n-length public Key, chars from baseString
"""
pubKeyGen()
main = ''
######
#@@@@@# shuffAlphaKeySel from alphaKeySpace
######
if main == 's':
"""
privKeyGen: generates 73 char private key, for i in baseString
"""
privKeyGen()
main=''
######
#@@@@@# ExitCond+command list
######
if main == 'x': #exit
exit()
if main == 'c':
print('"e" to encrypt, "d" to decrypt", "g" to generate a new public keySpace,\n"s" to select a private key, "k" to set shiftFactor, "x" to exit')
main = ''
if main == 'test':
print(alphaKeySpace)
main= ''
"""
Reset loop on nonValid entry
"""
else:
main=''
