An overview of all CTF challenges I checked out this year. Some even contain a write-up I wrote, although they can be quite sparse. Feel free to contact me about any of the challenges below. ^w^
Check out write-ups by my teammates on K3RN3L4RMY.com
HackPack CTF 2022
The challenges I wrote as guest author:
- Repeating Offense - Crypto 443 pts (20 solves) › Homomorphism attack on layered RSA + Paillier scheme(s)
- P(ai)^3 - Crypto 469 pts (15 solves) › Faulty Paillier scheme leaks primes and message
UMassCTF 2022
The challenges I wrote as guest author:
- HatMash - Crypto 500 pts (1 solve) › Hashing algorithm based on linear algebra
- Tomb of Tutanflagun - Crypto 500 pts (3 solves) › Multi-keyed Hill cipher with different key sizes
- Order of the Eight Apollonii - Crypto 500 pts (1 solve) › Secret sharing scheme based on the Apollonius problem
- MTRSASS - Crypto 500 pts (6 solves) › Merkle tree signature scheme based on RSA
- FastCrypt - Crypto 495 pts (24 solves) › Key-dependent sub-perm network leads to timing attack
LINE CTF 2022
- ss-puzzle - Crypto 100 pts (221 solves) › Simple XOR puzzle
- X Factor - Crypto 100 pts (102 solves) › Homomorphically combined unpadded RSA signatures to forge a signature
- Baby crypto revisited - Crypto 138 pts (48 solves) › ECDSA hidden number problem solved with lattice magic
- Forward-or - Crypto 145 pts (43 solves) › Present cipher meet-in-the-middle attack
- lazy-STEK - Crypto 290 pts (9 solves) ›
zer0pts CTF 2022
- Anti-Fermat - Crypto 90 pts (125 solves) › RSA with related primes allows for factorisation of public modulus
- CurveCrypto - Crypto 156 pts (36 solves) › EC encryption scheme susceptible to Coppersmith’s short-pad attack
- EDDH - Crypto 188 pts (24 solves) › Invalid curve attack on key exchange over Edwards curve
- OK - Crypto 289 pts (9 solves) ›
- Karen - Crypto 304 pts (8 solves) ›
UTCTF 2022
- Scrambled - Crypto 937 pts (54 solves) › Substitution cipher broken by frequency analysis
- Failed Hash Function - Crypto 974 pts (35 solves) › Keyed hash function leaks key bits through i/o analysis
- Sunset - Crypto 996 pts (15 solves) › Alternative diffie-hellman key exchange broken through simple linear algebra
DaVinciCTF 2022
- RSA - Crypto 87 pts (79 solves) › Factorisation of public modulus using leaked totient
- small weiner - Crypto 355 pts (72 solves) › RSA Weiner attack to recover small private exponent
- Secure Or Not Secure - Crypto 383 pts (65 solves) › Re-used key stream into cookie forgery
- Cwyptographic Owacle - Crypto 467 pts (35 solves) › ECDSA with predictable nonce generation leaks private key
DefCamp CTF 21-22 Online
- algorithm - Crypto 50 pts (94 solves) › Polynomial RSA still does not work
- raw-image - Crypto 179 pts (46 solves) › Image XOR
- malwy - Rev 200 pts (43 solves) ›
- rsa-factory - Crypto 450 pts (8 solves) ›
- P2DPI - Crypto 450 pts (8 solves) ›
ATR HAX by Trellix
- Modnar - Crypto 300 pts (? solves) › Time-seeded PRNG
DiceCTF 2022
- baby-rsa - Crypto 117 pts (162 solves) › (p-1)(q-1) divisible by e**2
- rejected - Crypto 117 pts (162 solves) › Simulated timing leaks internal state bits
- correlated - Crypto 117 pts (162 solves) › Noisy LFSR output recovered by fast correlation attack, or by luck :)
- commitment-issues - Crypto 117 pts (162 solves) ›
- pow-pow - Crypto 117 pts (162 solves) ›
- learning without errors - Crypto 117 pts (162 solves) ›
- shibari - Crypto 117 pts (162 solves) ›
- psych - Crypto 117 pts (162 solves) ›
Real World CTF 4th
- Treasure Hunter - Crypto ? pts (? solves) › Smart contract with sparse Merkle tree verification
TetCTF 2022
- shares - Crypto 216 pts (29 solves) ›
- shares_v2 - Crypto 804 pts (15 solves) ›
- algebra - Crypto 831 pts (14 solves) ›
- fault - Crypto 831 pts (14 solves) ›