Files
itesc_kw44/vignere.py
2018-10-29 23:22:23 +01:00

99 lines
2.9 KiB
Python
Executable File

#!/usr/bin/python3
import sys, getopt, os
def encrypt(string,key):
lowerstr=string.lower()
print("Encrypting "+lowerstr+" with key "+key)
strnums = []
keynums = []
resultnums = []
resultstring = ""
for c in lowerstr:
strnums.append(ord(c)-97)
print(strnums)
for c in key:
keynums.append(ord(c)-97)
print(keynums)
keypointer=0
for n in strnums:
resultnums.append((n+keynums[keypointer])%26)
keypointer = (keypointer+1) % (len(key))
print(resultnums)
for c in resultnums:
resultstring = resultstring+chr(c+97)
print(resultstring)
def decrypt(string,key):
lowerstr=string.lower()
print("Decrypting "+lowerstr+" with key "+key)
strnums = []
keynums = []
resultnums = []
resultstring = ""
for c in lowerstr:
strnums.append(ord(c)-97)
print(strnums)
for c in key:
keynums.append(ord(c)-97)
print(keynums)
keypointer=0
for n in strnums:
resultnums.append((n-keynums[keypointer])%26)
keypointer = (keypointer+1) % (len(key))
print(resultnums)
for c in resultnums:
resultstring = resultstring+chr(c+97)
print(resultstring)
def trigraphcount(string):
distances = {}
for i in range(0,len(string)-2):
trigraph = string[i:i+3]
index = 0
while index < len(string):
index = string.find(trigraph, index)
if index == -1:
break
print(trigraph+' found at', index)
if not trigraph in distances and index!=i:
distances[trigraph] = index - i
index += 3
#print(distances)
print(sorted(distances.items(), key=lambda x: x[1]))
def lettercount(string,dist):
letters = {}
for i in range(0,len(string)-dist,dist):
print(string[i:i+dist])
for c in string:
if c in letters:
letters[c] = letters[c]+1
else:
letters[c] = 1
print(letters)
def main(argv):
key = ""
try:
opts, args = getopt.getopt(argv,"hk:e:d:t:l:",["key=","encrypt=","decrypt=","trigraphs=","lettercount="])
except getopt.GetoptError:
print(os.path.basename(__file__)+' -k <key> -e <plain text>')
print(os.path.basename(__file__)+' -k <key> -d <encrypted text>')
sys.exit(2)
for opt, arg in opts:
if opt == '-h':
print(os.path.basename(__file__)+' -k <key> -e <plain text>')
print(os.path.basename(__file__)+' -k <key> -d <encrypted text>')
sys.exit()
elif opt in ("-k", "--key"):
key = arg
elif opt in ("-e", "--encrypt"):
encrypt(arg,key)
elif opt in ("-d", "--decrypt"):
decrypt(arg,key)
elif opt in ("-t", "--trigraphs"):
trigraphcount(arg)
elif opt in ("-l", "--lettercount"):
lettercount(arg,int(key))
if __name__ == '__main__':
main(sys.argv[1:])