reverseProhard

another-onion

DiceCTF 2026 Quals

Task: Self-decrypting onion binary with 256 layers, each requiring 2-byte key brute-force using SHA-NI derived keystream, 30-minute time limit. Solution: JIT execution with fork/COW isolation and 32 parallel workers achieving ~3500 candidates/sec.

$ ls tags/ techniques/
brute_forcexor_decryptionx86_64self_modifying_codesha256_nilayered_encryptionjit_executionfork_cowparallel_processingtime_limited
jit_code_executionfork_cow_isolationparallel_brute_forceoracle_based_decryptionmmap_fixed_addressptrace_state_extractionsignal_handler_recoveryshared_memory_optimization
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