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calculate key length

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Phillip Kühne 2018-10-31 21:51:25 +01:00
parent ef1636dfef
commit e3b7c1bd2d
1 changed files with 32 additions and 22 deletions
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54
vignere.py
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@ -1,5 +1,11 @@
#!/usr/bin/python3 #!/usr/bin/python3
import sys, getopt, os import sys, getopt, os, collections, math
def chartonum(char):
return ord(char)-97
def numtochar(int):
return chr(int+97)
def encrypt(string,key): def encrypt(string,key):
lowerstr=string.lower() lowerstr=string.lower()
@ -9,10 +15,10 @@ def encrypt(string,key):
resultnums = [] resultnums = []
resultstring = "" resultstring = ""
for c in lowerstr: for c in lowerstr:
strnums.append(ord(c)-97) strnums.append(chartonum(c))
print(strnums) print(strnums)
for c in key: for c in key:
keynums.append(ord(c)-97) keynums.append(chartonum(c))
print(keynums) print(keynums)
keypointer=0 keypointer=0
for n in strnums: for n in strnums:
@ -20,7 +26,7 @@ def encrypt(string,key):
keypointer = (keypointer+1) % (len(key)) keypointer = (keypointer+1) % (len(key))
print(resultnums) print(resultnums)
for c in resultnums: for c in resultnums:
resultstring = resultstring+chr(c+97) resultstring = resultstring+numtochar(c)
print(resultstring) print(resultstring)
def decrypt(string,key): def decrypt(string,key):
@ -31,18 +37,18 @@ def decrypt(string,key):
resultnums = [] resultnums = []
resultstring = "" resultstring = ""
for c in lowerstr: for c in lowerstr:
strnums.append(ord(c)-97) strnums.append(chartonum(c))
print(strnums) #print(strnums)
for c in key: for c in key:
keynums.append(ord(c)-97) keynums.append(chartonum(c))
print(keynums) #print(keynums)
keypointer=0 keypointer=0
for n in strnums: for n in strnums:
resultnums.append((n-keynums[keypointer])%26) resultnums.append((n-keynums[keypointer])%26)
keypointer = (keypointer+1) % (len(key)) keypointer = (keypointer+1) % (len(key))
print(resultnums) #print(resultnums)
for c in resultnums: for c in resultnums:
resultstring = resultstring+chr(c+97) resultstring = resultstring+numtochar(c)
print(resultstring) print(resultstring)
def trigraphcount(string): def trigraphcount(string):
@ -55,22 +61,26 @@ def trigraphcount(string):
if index == -1: if index == -1:
break break
print(trigraph+' found at', index) print(trigraph+' found at', index)
if not trigraph in distances and index!=i: offset = index - i
distances[trigraph] = index - i if not trigraph in distances and offset>0:
distances[trigraph] = [offset]
elif offset>0:
distances[trigraph].append(offset)
index += 3 index += 3
#print(distances) #print(distances)
print(sorted(distances.items(), key=lambda x: x[1])) #print(list(distances.values()))
dists = [item for sublist in list(distances.values()) for item in sublist]
#print(dists)
count = collections.Counter(dists)
most_commons = count.most_common(n=2)
print(most_commons)
key_len = math.gcd(most_commons[0][0], most_commons[1][0])
print(key_len)
lettercount(string,key_len)
#print(sorted(distances.items(), key=lambda x: x[1]))
def lettercount(string,dist): def lettercount(string,dist):
letters = {} pass
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): def main(argv):
key = "" key = ""