$ ctf42

Crypto CTF challenges

4,483 Crypto CTF challenges from 404 CTFs (2011–2026), 708 with writeups.

Top crypto techniques

#rsa 106 #xor 16 #lattice 16 #known-plaintext 12 #substitution-cipher 12 #lll 11 #crt 10 #diffie-hellman 9 #ecdsa 9 #discrete-log 9 #meet-in-the-middle 8 #caesar-cipher 8 #lfsr 8 #padding-oracle 8 #hastad-broadcast 7

Challenges

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Challenge CTF Weight Has
Leonine_Misbegotten 0xFUN 2026 17.74 files wu 1
Not_enough_part_1 KubSTU 2026 24.83 files wu 1
Quantum_Echo TraceBash 2026 25.00 files wu 1
State_Desync TraceBash 2026 25.00 files wu 1
The_Slot_Whisperer 0xFUN 2026 17.74 files wu 1
Young_Cryptography UIUCTF 2026 – files wu 1
positive_thinking UIUCTF 2026 – files wu 1
Almighty_Alphabet JerseyCTF 2025 24.73 files wu 1
Plutonian_Crypto SunshineCTF 2025 51.65 files wu 1
Speak_Friend_and_Enter DownUnderCTF 2025 91.66 files src wu 1
back_to_roots UIUCTF 2025 – files wu 1
bloCkchAin_ciphErS_sERcret NoHackNoCTF 2025 23.47 files wu 1
sol_rps corCTF 2025 82.00 files wu 1
the_shortest_crypto_chal UIUCTF 2025 – files wu 1
B4_the_B8 UMassCTF 2024 43.10 files wu 1
Clement ASIS 2024 Quals 66.25 files wu 1
Kassaskapet_2_Battre_tur_an_skicklighet CrateCTF 2024 – files wu 1
News_Of_The_World DawgCTF 2024 46.57 files wu 1
Rated_R H7CTF 2024 22.56 files wu 1
Reader_Exercise UMassCTF 2024 43.10 files wu 1
Shuffling_as_a_Service UMassCTF 2024 43.10 files wu 1
xnor BuckeyeCTF 2024 50.91 files wu 1
Appetizers BlueHens 2023 24.61 files wu 1
Git_Better BCACTF 2023 – files wu 1
Group_Project UIUCTF 2023 – files src wu 1
RUBXSCUBE VishwaCTF 2023 22.69 files wu 1
Shannon_Kent CyberHeroines 2023 23.94 files wu 1
You_get_extra_information_2 AmateursCTF 2023 24.54 files wu 1
ezdlp TJCTF 2023 – files wu 1
flag_art DownUnderCTF 2023 46.63 files wu 1
md5 TAMUctf 2023 – files wu 1
numbers-pensive TAMUctf 2023 – files wu 1
prng TAMUctf 2023 – files wu 1
shmooving TAMUctf 2023 – files wu 1
shmooving-3 TAMUctf 2023 – files wu 1
unbreakable BlueHens 2023 24.61 files wu 1
vinaigrette DiceCTF 2023 36.70 files wu 1
Pee_Kay_See_Ess_7 NahamCon 2022 24.61 files wu 1
Scrambled UTCTF 2022 – files wu 1
rs-ayyy-how-you-doin TAMUctf 2022 – files wu 1