add some problems in misc

Author: AngelKitty

misc/archive/zip/2015广州强网杯-爆破?/burst.zip

@@ -0,0 +1,64 @@
+from ngram_score import ngram_score
+from pycipher import Autokey
+import re
+from itertools import permutations
+
+qgram = ngram_score('quadgrams.txt')
+trigram = ngram_score('trigrams.txt')
+
+ctext = 'MPLRVFFCZEYOUJFJKYBXGZVDGQAURKXZOLKOLVTUFBLRNJESQITWAHXNSIJXPNMPLSHCJBTYHZEALOGVIAAISSPLFHLFSWFEHJNCRWHTINSMAMBVEXPZIZ'
+
+ctext = re.sub(r'[^A-Z]','',ctext.upper())
+# keep a list of the N best things we have seen, discard anything else
+
+class nbest(object):
+    def __init__(self,N=1000):
+        self.store = []
+        self.N = N
+
+    def add(self,item):
+        self.store.append(item)
+        self.store.sort(reverse=True)
+        self.store = self.store[:self.N]
+
+    def __getitem__(self,k):
+        return self.store[k]
+
+    def __len__(self):
+        return len(self.store)
+        
+#init
+N=100
+for KLEN in range(3,20):
+    rec = nbest(N)
+    for i in permutations('ABCDEFGHIJKLMNOPQRSTUVWXYZ',3):
+        key = ''.join(i) + 'A'*(KLEN-len(i))
+        pt = Autokey(key).decipher(ctext)
+        score = 0
+        for j in range(0,len(ctext),KLEN):
+            score += trigram.score(pt[j:j+3])
+        rec.add((score,''.join(i),pt[:30]))
+
+    next_rec = nbest(N)
+    for i in range(0,KLEN-3):
+        for k in xrange(N):
+            for c in 'ABCDEFGHIJKLMNOPQRSTUVWXYZ':
+                key = rec[k][1] + c
+                fullkey = key + 'A'*(KLEN-len(key))
+                pt = Autokey(fullkey).decipher(ctext)
+                score = 0
+                for j in range(0,len(ctext),KLEN):
+                    score += qgram.score(pt[j:j+len(key)])
+                next_rec.add((score,key,pt[:30]))
+        rec = next_rec
+        next_rec = nbest(N)
+    bestkey = rec[0][1]
+    pt = Autokey(bestkey).decipher(ctext)
+    bestscore = qgram.score(pt)
+    for i in range(N):
+        pt = Autokey(rec[i][1]).decipher(ctext)
+        score = qgram.score(pt)
+        if score > bestscore:
+            bestkey = rec[i][1]
+            bestscore = score       
+    print bestscore,'autokey, klen',KLEN,':"'+bestkey+'",',Autokey(bestkey).decipher(ctext)

misc/archive/zip/Abctf-2016-Zippy/zippy.zip

@@ -0,0 +1,29 @@
+'''
+Allows scoring of text using n-gram probabilities
+17/07/12
+'''
+from math import log10
+
+class ngram_score(object):
+    def __init__(self,ngramfile,sep=' '):
+        ''' load a file containing ngrams and counts, calculate log probabilities '''
+        self.ngrams = {}
+        for line in file(ngramfile):
+            key,count = line.split(sep) 
+            self.ngrams[key] = int(count)
+        self.L = len(key)
+        self.N = sum(self.ngrams.itervalues())
+        #calculate log probabilities
+        for key in self.ngrams.keys():
+            self.ngrams[key] = log10(float(self.ngrams[key])/self.N)
+        self.floor = log10(0.01/self.N)
+
+    def score(self,text):
+        ''' compute the score of text '''
+        score = 0
+        ngrams = self.ngrams.__getitem__
+        for i in xrange(len(text)-self.L+1):
+            if text[i:i+self.L] in self.ngrams: score += ngrams(text[i:i+self.L])
+            else: score += self.floor          
+        return score
+