crypto

Crypto

Scope: quick references for ciphers, alphabets, and sample ciphertexts seen in CTF crypto challenges. Use online solvers sparingly; many links point to dcode.fr or similar.

Quick wins

• Check for simple substitutions (pigpen, hexahue, runes, braille) before heavier cryptanalysis.
• For polyalphabetic ciphers, guess key length with repeating patterns, then try Vigenere/Gronsfeld.
• Test transposition ciphers (rail fence, scytale) on jumbled text with clear delimiters or braces.
• If you see hex/base64-like blobs, try decoding chains and look for inflate/rot variants.

Symbol substitution

• Alien predator language

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• Pigpen

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• Hexahue

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• Mary Stuart Code

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• Elder Futhark Rune

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• Alienese

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• Braille Alphabet

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• Birds on wire

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• Betamaze cipher

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• Lunar alphabet

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• Dotsies

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• Flag Semaphore

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• Music Sheet cipher

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• Keyboard shift

  • Example shifted with 1 key

  :ptr, O[di, od do,[;u fi,,u yrcy pg yjr [tomyomh smf yu[rdryyomh omfidytu/ :ptr, O[di, jsd nrrm yjr omfidytu\d dysmfstf fi,,u yrcy rbrt domvr yjr 26--d. ejrm sm imlmpem [tomyrt yppl s hs;;ru pg yu[r smf dvts,n;rf oy yp ,slr s yu[r d[rvo,rm nppl/ Oy jsd ditbobrf mpy pm;u gobr vrmyitord. niy s;dp yjr ;rs[ omyp r;rvytpmov yu[rdryyomh. tr,somomh rddrmyos;;u imvjsmhrf/
  

Numeral system

• Cistercian Monk Numerals
  • 

Poly-alphabetic cipher

• Vigenere Cipher

  • j3qrh4kgz3iptmyqxcw0zkm8i5xugs5lwl0lrwvirwktlqinexcw0zkmq5nqvpebpor5wqipqhw2ikzm4ipktzlr

• Gronsfeld Cipher

  • OQWKWPUVMYTIUSSTHHPI
  • key: 12345

Transposition cipher

• Rail fence

  • Ta _7N6DE7hlg:W3D_H3C31N__BD4ef sHR053F38N43D47 i33___NC

• Scytale cipher

  • hsggna0stiaeaetteyc4ehvdatyporwtyseefregrstaf_etposruouoy{qnirroiybrbs5edmothssavetc8hebhwuibihh72eyaoepmlvoet9lobulpkyenf4xpulsloinmelllisyassnousa31mebneedtctg_}eeedeboghbihpatesyyfolus1lnhnooeliotb5ebidfueonnactayseyl

Symmetric cryptography

• Fernet

  Token: gAAAAABWC9P7-9RsxTz_dwxh9-O2VUB7Ih8UCQL1_Zk4suxnkCvb26Ie4i8HSUJ4caHZuiNtjLl3qfmCv_fS3_VpjL7HxCz7_Q== Key: -s6eI5hyNh8liH7Gq0urPC-vzPgNnxauKvRO4g03oYI=

Synchronous stream cipher

• Rabbit

  • U2FsdGVkX1/+ydnDPowGbjjJXhZxm2MP2AgI

Examples (other)

• base64-inflate

  • 84gKNbRQNXcKT/X0TM7PTQXy4hPzUlSNzOKdEiuLchJzEhNVzV0A

• rot-47

  • v)*L*_F0<}@H0>F49023@FE0#@EN

• playfair

  • Dncnoqqfliqrpgeklwmppu

• Morse

  • -.. -.-. --- -.. . / -- --- .-. ... .

• UUnencode

  • 89FQA9WMD<V1A<V1S83DY.#<W3$Q,2TM]

• Chinese code

  • 606046152623600817831216121621196386

• SMS Packet Data Unit

  • 00110000910000FF2E547419646687CFA0F41CA4032993D321D5B8414D9BD348D1397C1293CE63C458753AB3915028B44901

• shadoks-cipher

  • BU ZO MEU BUGA BUBU BUZO BUMEU ZOGA ZOBU ZOZO

• Crack pseudo random number generator (python)

  • pseudo-random-number-generators-prng

  • import random
    # pip install mersenne-twister-predictor
    from mt19937predictor import MT19937Predictor
    
    predictor = MT19937Predictor()
    
    for _ in range(624):
        x = random.getrandbits(32)
        predictor.setrandbits(x, 32)  # Submit samples here
    
    # When enough samples are given, you can start predicting:
    assert random.getrandbits(32) == predictor.getrandbits(32)