Added Hex QR

count.py

@@ -20,6 +20,7 @@ for problem_name in problem_names:
 		pass
 		# print traceback.format_exc()
 
+problems.sort(key=lambda p: p.get("value"), reverse=True)
 print "Grand Total: %d" % len(problems)
 print "Category Breakdown:"
 
@@ -29,4 +30,4 @@ for category, count in categories:
 	print "  %s: %s" % (category, count)
 	for problem in problems:
 		if problem.get("category") != category: continue
-		print "    %s" % problem.get("title")
+		print "    %s [%s]" % (problem.get("title"), problem.get("value"))

qrt/description.md

@@ -0,0 +1 @@
+I've stumbled upon a very strange [QR code](${flag_png})... seems like it was generated with [this generator](http://hexqr.web.easyctf.com). What could it mean?

qrt/grader.py

@@ -0,0 +1,22 @@
+from cStringIO import StringIO
+from qrt import generate
+
+FLAG = "are_triangles_more_secure_than_squares?_%s}"
+
+def get_salt(random):
+	return "".join([random.choice("0123456789abcdef") for i in range(8)])
+
+def generate(random):
+	salt = get_salt(random)
+	im = generate("easyctf{%s}" % (FLAG % salt))
+	flag = StringIO()
+	im.save(buf, format="PNG")
+	return dict(files={
+		"flag.png": flag
+	})
+
+def grade(random, key):
+	salt = get_salt(random)
+	if key.find(FLAG % salt) >= 0:
+		return True, "Correct!"
+	return False, "Nope."

qrt/problem.yml

@@ -0,0 +1,5 @@
+title: Hex QR
+category: Programming
+value: 200
+author: mzhang
+autogen: true

qrt/qrt.py

@@ -0,0 +1,311 @@
+from PIL import Image, ImageDraw
+from math import ceil, sqrt
+
+ALTCONST = sqrt(3) / 2.0
+ISIZE = 784.0
+IMARGIN = 22.0
+
+def empty_hex(size):
+	c = 0
+	points = []
+	for i in range(2, size * 2 + 2, 2):
+		points.append([0] * i)
+	middle = []
+	for i in range(size * 2 - 1):
+		row = [0] * (size * 2)
+		middle.append(row)
+	epoints = list(row[:] for row in points[::-1])
+	return points + middle + epoints
+
+def intify(points):
+	return map(lambda c: (int(c[0]), int(c[1])), points)
+
+def draw_triangle(im, points, cell, size):
+	draw = ImageDraw.Draw(im)
+	# draw.polygon(points, outline=(0, 0, 0))
+	if cell:
+		draw.polygon(intify(points), fill=(0, 0, 0))
+	return im
+
+def getsection(i, size):
+	return 0 if i <= size - 1 else (1 if i < 3 * size - 1 else 2)
+
+def getspace(size):
+	return max(0, sum(len(filter(lambda a: a == 0, b)) for b in empty_hex(size)) - 2)
+
+def generate(string, debug=False):
+	size = 0
+	binstring = bin(int(string.encode("hex"), 16)).strip("0b")
+	while size < 2 or getspace(size + 1) < len(binstring):
+		size += 1
+	n = getspace(size)
+	# print size, len(binstring)
+	if debug: print "SIZE", size, " n =", n
+	im = Image.new("RGB", (int(ISIZE), int(ISIZE)), "white")
+	pattern = empty_hex(size)
+	# print len(binstring)
+	# print sum(len(i) for i in pattern)
+	pattern[0][len(string) % 2] = 1
+	curr = (1, 1 + len(string) % 2, 3 - len(string) % 2)
+	# 0 1
+	# 3 2
+	for c in range(n): # range(len(binstring)):
+		i, j, d = curr
+		row = pattern[i]
+		if c < len(binstring):
+			b = int(binstring[c])
+			pattern[i][j] = b
+		if c % 2 == 0:
+			pattern[i][j] ^= 1
+
+		section = getsection(i, size)
+		leftfacing = [j % 2 == 0, j % 2 != (i - size) % 2, j % 2 == 0][section]
+		if debug: print "c =", c, ", i =", i, ", j =", j, ", d =", d, ", s =", section, ", l =", leftfacing
+		if section == 0:
+			if getsection(i + 1, size) == 0:
+				if leftfacing:
+					if d == 0:
+						if j == 0:
+							curr = i + 1, j, (d + 2) % 4
+						else:
+							curr = i - 1, j - 1, d
+					elif d == 1 or d == 2:
+						curr = i, j + 1, d
+					elif d == 3:
+						curr = i + 1, j + 1, d
+				else:
+					if d == 0:
+						curr = i, j - 1, d
+					elif d == 1:
+						if j == len(row) - 1:
+							curr = i + 1, j + 2, (d + 2) % 4
+						else:
+							curr = i - 1, j - 1, d
+					elif d == 2:
+						curr = i + 1, j + 1, d
+					elif d == 3:
+						curr = i, j - 1, d
+			elif getsection(i + 1, size) == 1:
+				if leftfacing:
+					if d == 0:
+						if j == 0:
+							curr = i + 1, j, (d + 2) % 4
+						else:
+							curr = i - 1, j - 1, d
+					elif d == 1 or d == 2:
+						curr = i, j + 1, d
+					elif d == 3:
+						curr = i + 1, j, d
+				else:
+					if d == 0:
+						curr = i, j - 1, d
+					elif d == 1:
+						if j == len(row) - 1:
+							curr = i + 1, j, (d + 2) % 4
+						else:
+							curr = i - 1, j - 1, d
+					elif d == 2:
+						curr = i + 1, j, d
+					elif d == 3:
+						curr = i, j - 1, d
+		elif section == 1:
+			if getsection(i - 1, size) == 0:
+				if leftfacing:
+					if j == len(row) - 1:
+						if d == 1:
+							curr = i + 2, j, (d + 2) % 4
+						elif d == 2:
+							curr = i + 2, j, (d + 2) % 4
+						elif d == 3:
+							curr = i + 1, j, d
+					else:
+						if d == 0:
+							curr = i - 1, j, d
+						elif d == 1 or d == 2:
+							curr = i, j + 1, d
+						elif d == 3:
+							curr = i + 1, j, d
+				else:
+					if j == 0:
+						if d == 0:
+							curr = i + 2, j, (d + 2) % 4
+						elif d == 2:
+							curr = i + 1, j, d
+						elif d == 3:
+							curr = i + 2, j, (d + 2) % 4
+					else:
+						if d == 0 or d == 3:
+							curr = i, j - 1, d
+						elif d == 1:
+							curr = i - 1, j, d
+						elif d == 2:
+							curr = i + 1, j, d
+			elif getsection(i - 1, size) == 1:
+				if getsection(i + 1, size) == 1:
+					if leftfacing:
+						if j == len(row) - 1:
+							if d == 0:
+								curr = i - 1, j, d
+							elif d == 1:
+								curr = i + 2, j, (d + 2) % 4
+							elif d == 2:
+								curr = i + 2, j, (d + 2) % 4
+							elif d == 3:
+								curr = i + 1, j, d
+						else:
+							if d == 0:
+								curr = i - 1, j, d
+							elif d == 1 or d == 2:
+								curr = i, j + 1, d
+							elif d == 3:
+								curr = i + 1, j, d
+					else:
+						if j == 0:
+							if d == 0:
+								curr = i + 2, j, (d + 2) % 4
+							elif d == 1:
+								curr = i - 1, j, d
+							elif d == 2:
+								curr = i + 1, j, d
+							elif d == 3:
+								curr = i + 2, j, (d + 2) % 4
+						else:
+							if d == 0 or d == 3:
+								curr = i, j - 1, d
+							elif d == 1:
+								curr = i - 1, j, d
+							elif d == 2:
+								curr = i + 1, j, d
+				elif getsection(i + 1, size) == 2:
+					if leftfacing:
+						if j == len(row) - 1:
+							if d == 0:
+								curr = i - 1, j, d
+							elif d == 2:
+								curr = i + 1, j, (d + 2) % 4
+						else:
+							if d == 0:
+								curr = i - 1, j, d
+							elif d == 1:
+								curr = i, j + 1, d
+							elif d == 2:
+								curr = i, j + 1, d
+							elif d == 3:
+								curr = i + 1, j, d
+					else:
+						if d == 0:
+							curr = i, j - 1, d
+						elif d == 1:
+							curr = i - 1, j, d
+						elif d == 2:
+							curr = i + 1, j, d
+						elif d == 3:
+							if j == 0:
+								curr = i + 1, j, (d + 2) % 4
+							else:
+								curr = i, j - 1, d
+		elif section == 2:
+			if getsection(i - 1, size) == 1:
+				if leftfacing:
+					if d == 0:
+						curr = i - 1, j, d
+					elif d == 1:
+						curr = i, j + 1, d
+					elif d == 2:
+						curr = i, j + 1, d
+					elif d == 3:
+						if j == 0:
+							curr = i + 1, j, (d + 2) % 4
+						else:
+							curr = i + 1, j - 1, d
+				else:
+					if d == 0 or d == 3:
+						curr = i, j - 1, d
+					elif d == 1:
+						curr = i - 1, j, d
+					elif d == 2:
+						if j == len(row) - 1:
+							curr = i + 1, j - 2, (d + 2) % 4
+						else:
+							curr = i + 1, j - 1, d
+			elif getsection(i - 1, size) == 2:
+				if leftfacing:
+					if d == 0:
+						curr = i - 1, j + 1, d
+					elif d == 1 or d == 2:
+						curr = i, j + 1, d
+					elif d == 3:
+						if j == 0:
+							curr = i + 1, j, (d + 2) % 4
+						else:
+							curr = i + 1, j - 1, d
+				else:
+					if j == len(row) - 1:
+						if d == 0:
+							curr = i, j - 1, d
+						elif d == 1:
+							curr = i - 1, j + 1, d
+						elif d == 2:
+							curr = i + 1, j - 2, (d + 2) % 4
+					else:
+						if d == 0 or d == 3:
+							curr = i, j - 1, d
+						elif d == 1:
+							curr = i - 1, j + 1, d
+						elif d == 2:
+							curr = i + 1, j - 1, d
+	# for i in range(len(pattern)):
+	# 	for j in range(len(pattern[i])):
+	# 		section = 0 if i <= size - 1 else (1 if i < 3 * size - 1 else 2)
+	# 		leftfacing = [j % 2 == 0, j % 2 != (i - size) % 2, j % 2 == 0][section]
+	# 		if not leftfacing:
+	# 			print j,
+	# 	print
+	sidelen = (ISIZE - IMARGIN * 2) / (2.0 * size)
+	altitude = sidelen * ALTCONST
+	# print sidelen, altitude
+	for i in range(len(pattern)):
+		section = getsection(i, size)
+		row = pattern[i]
+		rowleft = (ISIZE / 2) - (altitude * len(row) / 2)
+		if section % 2 == 0:
+			evenrow = i % 2 == 0
+			for j in range(len(row)):
+				cell = row[j]
+				top = ceil(i / 2.0) * sidelen - (0.5 * sidelen if not evenrow else 0) + IMARGIN
+				bottom = top + sidelen
+				if j % 2 == 0:
+					points = [
+						(rowleft + altitude * j, top + sidelen / 2),
+						(rowleft + altitude * (j + 1), top), (rowleft + altitude * (j + 1), bottom)
+					]
+				else:
+					points = [
+						(rowleft + altitude * (j + 1), top + sidelen / 2),
+						(rowleft + altitude * j, top), (rowleft + altitude * j, bottom)
+					]
+				draw_triangle(im, points, cell, size)
+		else:
+			evenrow = (i - size) % 2 == 1
+			for j in range(len(row)):
+				cell = row[j]
+				top = ceil(i / 2.0) * sidelen - (0.5 * sidelen if i % 2 == 1 else 0) + IMARGIN
+				bottom = top + sidelen
+				if j % 2 == (i - size) % 2:
+					points = [
+						(rowleft + altitude * (j + 1), top + sidelen / 2),
+						(rowleft + altitude * j, top), (rowleft + altitude * j, bottom)
+					]
+				else:
+					points = [
+						(rowleft + altitude * j, top + sidelen / 2),
+						(rowleft + altitude * (j + 1), top), (rowleft + altitude * (j + 1), bottom)
+					]
+				draw_triangle(im, points, cell, size)
+	return im
+
+# im = generate("easyctf{are_triangles_more_secure_than_squares?}")
+# im.save("flag.png")
+
+# for i in range(40, 60):
+# 	generate("A" * i, "/tmp/%d.png" % i)

qrt/server.py

@@ -0,0 +1,30 @@
+from flask import Flask, request
+from qrt import generate
+from base64 import b64encode
+from binascii import b2a_base64
+from cStringIO import StringIO
+from traceback import format_exc
+
+app = Flask(__name__)
+
+@app.route("/", methods=["GET", "POST"])
+def index():
+	try:
+		html = "<title>hex qr</title><form method=post>enter a string: <input type=text name=text value='%s' autocomplete=off autofocus /></form>"
+		if request.method == "POST":
+			if not request.form.get("text"):
+				html %= ""
+				html += "<p>empty</p>"
+			else:
+				html %= request.form["text"]
+				im = generate(request.form["text"])
+				buf = StringIO()
+				im.save(buf, format="JPEG")
+				html += "<img src='data:image/jpeg;base64,%s'>" % b2a_base64(buf.getvalue())
+		else:
+			html %= ""
+		return html
+	except:
+		return "<!--\nthere's a problem, here's the details:\n%s\n-->" % format_exc()
+
+app.run(host="0.0.0.0", port=5000)