cryptomedium
POPO (Paillier Operation Performance Optimizer)
hackthebox
Task: Paillier homomorphic encryption system with menu-driven interface and encrypted flag. Solution: Exploit optim state bug to skip exponentiation, recover blinding factor via nonce reuse, extract gm, and use validate_role oracle to leak private key λ for decryption.
$ ls tags/ techniques/
modular_arithmeticnonce_reusepaillierhomomorphic_encryptionstate_machine_bugblinding_factoroptimization_flaw
blinding_factor_cancellationstate_manipulationpaillier_decryptionoracle_abuseprivate_key_leak
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