cryptomedium

Embryonic Plant

hackthebox

Task: LCG-based PRNG combined with multi-prime RSA (n=p*q*r), given 5 consecutive LCG outputs and AES-encrypted flag with key derived from RSA private exponent. Solution: Recover LCG modulus r via GCD of t_{i+1}*t_{i-1}-t_i^2 values, then recover p and q from LCG equations, factor n, compute d, decrypt AES.

$ ls tags/ techniques/
aes_ecb_decryptionlcg_state_recoverylcg_modulus_recovery_via_gcdmulti_prime_rsa_factorization

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