Initial commit

Author: ItzSomebody

.gitignore

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+*.swp
+
+node_modules
+*.pyc
+
+.DS_Store
+
+.rcds-cache

README.md

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+# redpwnctf-2020-challenges

crypto/12-shades-of-redpwn/challenge.yaml

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+name: 12-shades-of-redpwn
+author: Boolean
+description: |-
+  Everyone's favorite guess god Tux just sent me a flag that he somehow encrypted with a color wheel!
+  
+  I don't even know where to start, the wheel looks more like a clock than a cipher... can you help me crack the code?
+flag:
+  file: ./flag.txt
+provide:
+- ./color-wheel.jpg
+- ./ciphertext.jpg

crypto/12-shades-of-redpwn/ciphertext.jpg

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+flag{9u3ss1n9_1s_4n_4rt}

crypto/12-shades-of-redpwn/color-wheel.jpg

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+#!/usr/bin/env python3
+
+# values from transcribed-ciphertext.jpg
+b12_ctxt = [
+	[8,6],
+	[9,0],
+	[8,1],
+	[8,7],
+	[10,3],
+	[4,9],
+	[9,9],
+	[4,3],
+	[9,7],
+	[9,7],
+	[4,1],
+	[9,2],
+	[4,9],
+	[7,11],
+	[4,1],
+	[9,7],
+	[7,11],
+	[4,4],
+	[9,2],
+	[7,11],
+	[4,4],
+	[9,6],
+	[9,8],
+	[10,5]
+]
+
+flag = ''
+
+for a,b in b12_ctxt:
+    n = a * 12 + b
+    flag += chr(n)
+
+print(flag)

crypto/12-shades-of-redpwn/flag.txt

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+n: 5028492424316659784848610571868499830635784588253436599431884204425304126574506051458282629520844349077718907065343861952658055912723193332988900049704385076586516440137002407618568563003151764276775720948938528351773075093802636408325577864234115127871390168096496816499360494036227508350983216047669122408034583867561383118909895952974973292619495653073541886055538702432092425858482003930575665792421982301721054750712657799039327522613062264704797422340254020326514065801221180376851065029216809710795296030568379075073865984532498070572310229403940699763425130520414160563102491810814915288755251220179858773367510455580835421154668619370583787024315600566549750956030977653030065606416521363336014610142446739352985652335981500656145027999377047563266566792989553932335258615049158885853966867137798471757467768769820421797075336546511982769835420524203920252434351263053140580327108189404503020910499228438500946012560331269890809392427093030932508389051070445428793625564099729529982492671019322403728879286539821165627370580739998221464217677185178817064155665872550466352067822943073454133105879256544996546945106521271564937390984619840428052621074566596529317714264401833493628083147272364024196348602285804117877
+e: 65537
+c: 3832859959626457027225709485375429656323178255126603075378663780948519393653566439532625900633433079271626752658882846798954519528892785678004898021308530304423348642816494504358742617536632005629162742485616912893249757928177819654147103963601401967984760746606313579479677305115496544265504651189209247851288266375913337224758155404252271964193376588771249685826128994580590505359435624950249807274946356672459398383788496965366601700031989073183091240557732312196619073008044278694422846488276936308964833729880247375177623028647353720525241938501891398515151145843765402243620785039625653437188509517271172952425644502621053148500664229099057389473617140142440892790010206026311228529465208203622927292280981837484316872937109663262395217006401614037278579063175500228717845448302693565927904414274956989419660185597039288048513697701561336476305496225188756278588808894723873597304279725821713301598203214138796642705887647813388102769640891356064278925539661743499697835930523006188666242622981619269625586780392541257657243483709067962183896469871277059132186393541650668579736405549322908665664807483683884964791989381083279779609467287234180135259393984011170607244611693425554675508988981095977187966503676074747171

crypto/12-shades-of-redpwn/solve/b12-color-wheel.jpg

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+name: 4k-rsa
+author: Boolean
+description: |-
+  Only n00bz use 2048-bit RSA. True gamers use keys that are at least 4k bits long, no matter how many primes it takes...
+flag:
+  file: ./flag.txt
+provide:
+- ./4k-rsa-public-key.txt

crypto/12-shades-of-redpwn/solve/solve.py

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+flag{t0000_m4nyyyy_pr1m355555}

crypto/12-shades-of-redpwn/solve/transcribed-ciphertext.jpg

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+#!/usr/bin/env sage
+
+from Crypto.Util.number import long_to_bytes
+
+n = 5028492424316659784848610571868499830635784588253436599431884204425304126574506051458282629520844349077718907065343861952658055912723193332988900049704385076586516440137002407618568563003151764276775720948938528351773075093802636408325577864234115127871390168096496816499360494036227508350983216047669122408034583867561383118909895952974973292619495653073541886055538702432092425858482003930575665792421982301721054750712657799039327522613062264704797422340254020326514065801221180376851065029216809710795296030568379075073865984532498070572310229403940699763425130520414160563102491810814915288755251220179858773367510455580835421154668619370583787024315600566549750956030977653030065606416521363336014610142446739352985652335981500656145027999377047563266566792989553932335258615049158885853966867137798471757467768769820421797075336546511982769835420524203920252434351263053140580327108189404503020910499228438500946012560331269890809392427093030932508389051070445428793625564099729529982492671019322403728879286539821165627370580739998221464217677185178817064155665872550466352067822943073454133105879256544996546945106521271564937390984619840428052621074566596529317714264401833493628083147272364024196348602285804117877
+e = 65537
+c = 3832859959626457027225709485375429656323178255126603075378663780948519393653566439532625900633433079271626752658882846798954519528892785678004898021308530304423348642816494504358742617536632005629162742485616912893249757928177819654147103963601401967984760746606313579479677305115496544265504651189209247851288266375913337224758155404252271964193376588771249685826128994580590505359435624950249807274946356672459398383788496965366601700031989073183091240557732312196619073008044278694422846488276936308964833729880247375177623028647353720525241938501891398515151145843765402243620785039625653437188509517271172952425644502621053148500664229099057389473617140142440892790010206026311228529465208203622927292280981837484316872937109663262395217006401614037278579063175500228717845448302693565927904414274956989419660185597039288048513697701561336476305496225188756278588808894723873597304279725821713301598203214138796642705887647813388102769640891356064278925539661743499697835930523006188666242622981619269625586780392541257657243483709067962183896469871277059132186393541650668579736405549322908665664807483683884964791989381083279779609467287234180135259393984011170607244611693425554675508988981095977187966503676074747171
+
+primes = ecm.factor(n)
+
+phi = prod(p-1 for p in primes)
+d = inverse_mod(e,phi)
+
+m = pow(c,d,n)
+flag = long_to_bytes(m)
+
+print(flag)

crypto/4k-rsa/4k-rsa-public-key.txt

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+name: alien-transmissions-v2
+author: BrownieInMotion
+description: |-
+  The aliens are at it again! We've discovered that their communications are in
+  base 512 and have transcribed them in base 10. However, it seems like they used
+  XOR encryption twice with two different keys! We do have some information:
+  - This alien language consists of words delimitated by the character represented as 481
+  - The two keys appear to be of length 21 and 19
+  - The value of each character in these keys does not exceed 255
+  Find these two keys for me; concatenate their ASCII encodings and wrap it in
+  the flag format.
+flag:
+  file: ./flag.txt
+provide:
+- ./encrypted.txt

crypto/4k-rsa/challenge.yaml

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+from random import randint
+from itertools import cycle
+keys = ["h3r3'5_th3_f1r5t_h4lf", "_th3_53c0nd_15_th15"]
+deliminator = 481
+
+print("Generating message...")
+message = []
+for _ in range(100000):
+    wordlen = randint(8, 12)
+    message.append(deliminator)
+    for _ in range(wordlen):
+        message.append(randint(0, 511))
+message = message[1:]
+
+print("Encrypting message...")
+for key in keys:
+    for i, (m, b) in enumerate(zip(message, cycle(key))):
+        message[i] = m ^ ord(b)
+
+print("Creating output...")
+string = ""
+for m in message:
+    string += str(m) + "\n"
+f = open("encrypted.txt", "w+")
+f.write(string)
+f.close()