CTF challenges & writeups

134 challenges in family ⊕ crypto:classical ✕ clear · browse all techniques

Challenge	CTF	Weight	Category	Has
Borrowed_Memory #bytecode-vm-emulation #xorshift-table-regeneration #checksum-guided-debugging #xor-decryption	BDSec 2026	15.62	Reverse	files wu 1
cake #vigenere-cipher	Bhackari 2026	–	Misc	files wu 1
Control_Freak_1 #custom-cipher-reversing	LYKNCTF 2026	–	Reverse	files wu 1
Buried_Treasure #multi-stage-unpacking #memfd-create #xor #strace-dump	RITSEC 2026	–	Reverse	files wu 1
obfpyscated #python-obfuscation #xor #aes	RITSEC 2026	–	Reverse	files wu 1
Misdirection #bacon-cipher #24-letter-alphabet	ScriptCTF 2026	–	Crypto	files wu 1
dotsbedashing #morse-code #xor #bit-rotation	VuwCTF 2026	25.00	Reverse	files wu 1
ilikewords #xor #kaprekar-constant	VuwCTF 2026	25.00	Reverse	files wu 1
Clockwork #xor	EnigmaXplore 2025	–	Reverse	files wu 1
Crispy_Kelp #xor-cipher	IrisCTF 2025	34.30	Reverse	files wu 1
Cryptoclock #known-plaintext-xor	NahamCon 2025	53.77	Crypto	files wu 1
Palatine_Pack #reversing #xor	SunshineCTF 2025	51.65	Reverse	files wu 1
XOR_101 #xor #repeating-key	squ1rrel 2025	24.25	Crypto	files wu 1
This_is_NOT_the_flag #xor-bruteforce	BCACTF 2024	–	Misc	files wu 1
Vinegar_Times_3 #vigenere-cipher	BCACTF 2024	–	Crypto	files wu 1
XOR #xor-decryption	BCACTF 2024	–	Reverse	files wu 1
unoriginal #xor-cipher	ImaginaryCTF 2024	49.81	Reverse	files wu 1
PasswordManager #xor-cipher	JerseyCTF 2024	21.26	Pwn	files wu 1
X_Marked_the_Spot #xor #repeating-key	UIUCTF 2024	–	Crypto	files wu 2
Export_Grade_Cipher #chosen-plaintext #custom-cipher	UofTCTF 2024	23.90	Crypto	files wu 1
repeat #repeating-key-xor	UofTCTF 2024	23.90	Crypto	files wu 3
Game_Graphics_Debugging #dll-hijacking #tls-callback #xor	WolvCTF 2024	35.25	Reverse	files wu 2
Vinegar #vigenere-cipher	n00bzCTF 2024	24.23	Crypto	files wu 3
Vinegar_2 #vigenere-cipher	n00bzCTF 2024	24.23	Crypto	files wu 2
Not_So_Smooth #linear-congruence-recovery #modular-arithmetic #xor	1337UP 2023	24.23	Crypto	files wu 1
RevEng #xor-decryption #ghidra	BYUCTF 2023	–	Reverse	files wu 1
B1Tz_and_B0tZ #multi-layer-encoding #binary #hex #rot13	DEADFACE 2023	–	Crypto	files wu 1
HAM_JAM #morse-code #codablock-barcode #vigenere	DEADFACE 2023	–	Crypto	files wu 1
Letter_Soup #word-search #rot13	DEADFACE 2023	–	Crypto	files wu 1
Off_the_Rails #rail-fence-cipher	DEADFACE 2023	–	Crypto	files wu 1
brain-hurt #xor	HSCTF 2023	–	Reverse	files wu 1
cupcakes #vigenere	HSCTF 2023	–	Crypto	files wu 1
trios #substitution-cipher	HSCTF 2023	–	Crypto	files wu 2
greek-cipher #substitution-cipher	LA 2023	–	Crypto	files wu 2
hill-easy #hill-cipher	LA 2023	–	Crypto	files wu 1
one-more-time-pad #known-plaintext-xor	LA 2023	–	Crypto	files wu 2
Python_Garbage_Compiler #python-obfuscation #seeded-prng #xor	PatriotCTF 2023	24.52	Reverse	files wu 1
Either_or_Neither_nor #xor #repeating-key #bruteforce	RITSEC 2023	–	Crypto	files wu 1
CrossingTheRedSea #brainfuck #esolang #substitution-cipher	VishwaCTF 2023	22.69	Crypto	files wu 2
HomeworkHelp #reversing #buffer-overflow #xor	WolvCTF 2023	24.33	Reverse	files wu 2

Challenges