some small fixes

Cryptography/md5/brute_force_hex_digest_chars.py

@@ -0,0 +1,41 @@
+'''
+EXAMPLE FROM ASIS 2013, WITH THE CONCATENATED HASH:
+
+7e1321b3c8423b30c1cb077a2e3ac4f0a2a551a6458a8de22446cc76d639a9e98fc42c6cddf9966db3b09e843650343578b04d5e377d298e78455efc5ca404d5f4c9385f1902f7334b00b9b4ecd164de8bf8854bebe108183caeb845c7676ae48fc42c6ddf9966db3b09e84365034357327a6c4304ad5938eaf0efb6cc3e53dc7ff9ea9a069bd793691c422fb818c07b
+
+'''
+
+import md5
+
+
+# the entire flag
+
+m1 = '7e1321b3c8423b30c1cb077a2e3ac4f0'
+m2 = 'a2a551a6458a8de22446cc76d639a9e9'
+m3 = '8fc42c6ddf9966db3b09e84365034357'
+m4 = '8b04d5e3775d298e78455efc5ca404d5'
+m5 = 'f4c9385f1902f7334b00b9b4ecd164de'
+m6 = '8bf8854bebe108183caeb845c7676ae4'
+m7 = '8fc42c6ddf9966db3b09e84365034357'
+m8 = '327a6c4304ad5938eaf0efb6cc3e53dc'
+m9 = '7ff9ea9a069bd793691c422fb818c07b'
+
+all = [m1, m2, m3, m4, m5, m6, m7, m8, m9]
+
+for m in all:
+    a = md5.md5(m)
+    print "md5 object", a
+    print "digest(): ", a.digest()
+    print "hexdigest(): ", a.hexdigest()
+    print
+
+
+
+
+
+# last part
+
+for a in "abcdef0123456789":
+    for b in "abcdef0123456789":
+        if "7ff9ea9a069bd793691c422fb818c07b" == md5.md5('ASIS_' + a + b).hexdigest():
+            print 'ASIS_' + a + b

Cryptography/sha/sha-256-bruteforce.py

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+'''
+from asis 2013: The last crypto (binary numbers) was very puzzling. We couldn’t decipher it. But a few minutes before the CTF ending, we noticed we could brute-force the 6 missing characters offline, because in each task, there was a client-side verification with a sha-256 hash. For this task, the hash of the flag was 6307c5441ebac07051e3b90d53c3106230dd9aa128601dcd5f63efcf824ce1ba. A quick brute-force in Python revealed us the missing chars, and therefore, the final flag to submit!
+'''
+
+
+import hashlib, itertools
+hash = '6307c5441ebac07051e3b90d53c3106230dd9aa128601dcd5f63efcf824ce1ba'
+ch = 'abcdef0123456789'
+for a, b, c, d, e, f in itertools.product(ch, ch, ch, ch, ch, ch):
+    if hashlib.sha256('ASIS_a9%s00f497f2eaa4372a7fc21f0d' % (a + b + c + d + e + f)).hexdigest() == hash:
+        print 'ASIS_a9%s00f497f2eaa4372a7fc21f0d' % (a + b + c + d + e + f)

Cryptography/sha/sha-256-bruteforce_remove_123456789x.py

@@ -0,0 +1,24 @@
+'''
+from asis 2013
+'''
+
+from itertools import permutations
+from hashlib import sha256
+
+def test(s):
+  e = '9f2a579716af14400c9ba1de8682ca52c17b3ed4235ea17ac12ae78ca24876ef'
+  return sha256('ASIS_' + s).hexdigest() == e
+
+m = '3c6a1c371b381c943065864b95ae5546'
+s = '12456789x'
+for p in permutations(s):
+    def f(sub, c):
+        if c in sub:
+            return sub[c]
+        else:
+            return c
+    sub = {c : d for c, d in zip(s, p)}
+    z = ''.join(f(sub, c) for c in m)
+    if test(z):
+        print z
+        break

Steganography/dec_image/color_crypto.py

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+#!/usr/bin/env python
+
+from PIL import Image
+import random
+
+def get_color(x, y, r):
+	n = (pow(x, 3) + pow(y, 3)) ^ r
+	return (n ^ ((n >> 8) << 8 ))
+
+flag_img = Image.open("flag.png")
+im = flag_img.load()
+r = random.randint(1, pow(2, 256))
+print flag_img.size
+
+enc_img = Image.new(flag_img.mode, flag_img.size)
+enpix = enc_img.load()
+
+for x in range(flag_img.size[0]):
+	for y in range(flag_img.size[1]):
+		t = random.randint(1, pow(2, 256)) % 250
+		enpix[x,y] = t
+
+
+for x in range(flag_img.size[0]):
+	for y in range(flag_img.size[1]):
+		if im[x,y] < 250 :
+			s = get_color(x, y, r)
+			enpix[x,y] = s
+		
+enc_img.save('enc' + '.png')

Steganography/dec_image/color_crypto_dec.py

@@ -0,0 +1,38 @@
+#!/usr/bin/python
+
+from PIL import Image
+import random
+import operator
+
+def get_color(x, y, r):
+	n = (pow(x, 3) + pow(y, 3)) ^ r
+	return (n ^ ((n >> 8) << 8 ))
+
+flag_img = Image.open("flag.png")
+im = flag_img.load()
+print flag_img.size
+
+enc_img = Image.new(flag_img.mode, flag_img.size)
+enpix = enc_img.load()
+
+d = {}
+for i in range(0, 256):
+	d[i] = 0
+
+for x in range(flag_img.size[0]):
+	for y in range(flag_img.size[1]):
+		enpix[x,y] = 0
+		r = im[x, y] ^ ((pow(x, 3) + pow(y, 3)) % 256)
+		d[r] += 1
+
+use = max(d.iteritems(), key=operator.itemgetter(1))[0]
+
+for x in range(flag_img.size[0]):
+	for y in range(flag_img.size[1]):
+		r = im[x, y] ^ ((pow(x, 3) + pow(y, 3)) % 256)
+		if r == use:
+			enpix[x, y] = 255
+
+print use
+
+enc_img.save('dec' + '.png')

Steganography/xor_image_broken/xor_image.py

@@ -0,0 +1,17 @@
+from PIL import Image
+img = Image.open('steg100.png')
+
+strbit1 = ''
+for y in range(0, img.size[1], 19):
+	for x in range(0, img.size[0], 19):
+		r = img.getpixel((x, y))
+		strbit1 += str(r & 1)
+
+strbit2 = ''
+for y in range(171, 171 + 19):
+	for x in range(171, 171 + 19):
+		a = img.getpixel((x, y))
+		strbit2 += str(a & 1)
+
+xored = ''.join(str(int(A) ^ int(B)) for A, B in zip(strbit1, strbit2))
+print ''.join(chr(int(xored[i:i + 8], 2)) for i in range(0, len(xored), 8))

Steganography/xor_image_broken/xor_image.py~

@@ -0,0 +1,18 @@
+from PIL import Image
+img = Image.open('steg100.png')
+
+strbit1 = ''
+for y in range(0, img.size[1], 19):
+	for x in range(0, img.size[0], 19):
+		print img.getpixel((x, y))
+		print r
+		strbit1 += str(r & 1)
+
+strbit2 = ''
+for y in range(171, 171 + 19):
+	for x in range(171, 171 + 19):
+		a = img.getpixel((x, y))
+		strbit2 += str(a & 1)
+
+xored = ''.join(str(int(A) ^ int(B)) for A, B in zip(strbit1, strbit2))
+print ''.join(chr(int(xored[i:i + 8], 2)) for i in range(0, len(xored), 8))

Useful_Scripts/binary_dot_symbols.py

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+'''
+..    . .. .  . .. ...  ... .   . ..... ..    . ..  ..  ...  . 
+....... ....... ....... ....... ....... ....... ....... .......
+
+..    . .. .  . ..  .   . ..... .. .... ..  ..  . ..... .. ... 
+....... ....... ....... ....... ....... ....... ....... .......
+
+.. .... . ..... ..  ... .. .    .. .... ...  .. ... .   ...  ..
+....... ....... ....... ....... ....... ....... ....... .......
+'''
+
+
+s="""1100001 1101001 1101110 1110100 1011111 1100001 1100110 1110010 1100001 1101001 1100100 1011111 1101111 1100110 1011111 1101110 1101111 1011111 1100111 1101000 1101111 1110011 1110100 1110011"""
+
+a = ''.join(chr(int(i, 2)) for i in s.replace("\n"," ").split(' '))
+
+print a