Crypto CTF challenges

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

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Challenges

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Challenge	CTF	Weight	Has
Limited_2 #prng-seed-bruteforce #time-based-seed	WolvCTF 2024	35.25	files wu 1
casino2 #prng-prediction #golang	TetCTF 2023	53.89	files wu 1
FryingInMotion #prng-prediction	Dragon 2020	98.00	files wu 1
The_Phantom_Menace #private-key-disclosure	LakeCTF 2025 Quals	–	files wu 1
RSA_Eclipse #primes-near-power-of-two	L3akCTF 2026	34.47	files wu 1
Random_Inator #predictable-prng-key	Kashi 2025	21.78	files wu 1
crypto-casino #predictable-on-chain-randomness #keccak-prng #weak-seed	0x41414141 2021	–	files wu 1
PRSA #polynomial-ring-rsa #gf(2)-polynomial-factorization	BackdoorCTF 2023	–	files wu 1
Poly321 #polynomial-inversion	HeroCTF 2022	51.22	files wu 1
Poly_Expo_go_BRRRRR #polynomial-factorization	K3RN3LCTF 2021	24.37	files wu 1
Ez_Part #pohlig-hellman	LakeCTF 2025 Quals	–	files wu 1
Nostego #png-bit-transform #visual-recovery	ALLES 2021	–	files wu 1
SecureImageEncryption #permutation-cipher #chosen-plaintext	SekaiCTF 2022	24.86	files wu 1
shufflebox #permutation	DownUnderCTF 2024	68.04	files src wu 1
nft #path-traversal #os-path-join	Codegate 2022 Quals	–	files wu 1
HashCat #password-cracking #rar	TrollCAT 2021	21.87	files wu 1
regulus-satrapa #partial-key-exposure	HSCTF 2021	–	files wu 1
zipfel #pairing-attack	hxp 2021	99.41	files wu 1
Shrine_of_the_Sweating_Buddha #paillier-predictable-randomness	K3RN3LCTF 2021	24.37	files wu 1
morph-master #paillier #homomorphic	TJCTF 2022	–	files wu 1
witches_symmetric_exam #padding-oracle #ofb #gcm	SECCON 2022 Quals	97.90	files wu 1
cerberus #padding-oracle #cbc #decryption-oracle	SECCON 2021	–	files wu 1
ComicallyBadCrypto #padding-oracle #aes-cbc #bit-flipping	PatriotCTF 2022	24.52	files wu 1
PADGROUNDS #padding-oracle #aes-cbc	TFC 2024	–	files wu 1
Careless_Padding #padding-oracle	HITCON 2023 Quals	99.75	files wu 1
n1ogin #padding-oracle	N1CTF 2021	53.54	files wu 1
Giant_log #p-adic-discrete-log	m0leCon 2021 Quals	24.55	files wu 1
Symmetry_2 #out-of-bounds-write	KalmarCTF 2024	24.21	files wu 1
S+7 #oulipo #n+7 #dictionary-substitution	WPICTF 2021	–	files wu 1
secure-enclave #on-chain-secret-exposure #transaction-input-data-disclosure	0x41414141 2021	–	files wu 1
Immiscible #oil-and-vinegar	L3akCTF 2026	34.47	files wu 1
CSC265 #oblivious-transfer-attack	L3akCTF 2026	34.47	files wu 1
import_numpy_as_MT #numpy-mt19937 #seed-bruteforce #aes-cbc	Zh3r0 2021	–	files src wu 1
leftovers #nth-roots-of-unity #modular-roots	PBjar 2021	23.18	files wu 1
Boombastic #nonce-reuse	FwordCTF 2021	24.42	files wu 1
Greatest_Hits_1_of_4 #nested-encoding	BlueHens 2023	24.61	files wu 1
TVAsTrap #nested-base64	Engineer 2022	22.65	files wu 1
TruthAndFalsehood #nested-base64	BYUCTF 2022	–	files src wu 1
IS_THIS_LCG #multiprime-rsa #truncated-lcg #ec-lcg #lll (lll-lattice-reduction)	RCTF 2022	–	files wu 1
B1Tz_and_B0tZ #multi-layer-encoding #binary #hex #rot13	DEADFACE 2023	–	files wu 1