nx_hmac_drbg_wasm.nx

nx_hmac_drbg_wasm.nx -- HMAC-DRBG with SHA-256 per NIST SP 800-90A §10.1.2. State: K (32 B), V (32 B). Update(provided_data): K = HMAC(K, V || 0x00 || provided_data) V = HMAC(K, V) if provided_data is empty: return K = HMAC(K, V || 0x01 || provided_data) V = HMAC(K, V) Instantiate(entropy, nonce, personalisation): K = 32 zero bytes V = 32 0x01 bytes Update(entropy || nonce || personalisation) Reseed(entropy, additional_input): Update(entropy || additional_input) Generate(N, additional_input): if additional_input non-empty: Update(additional_input) tmp = "" while len(tmp) < N: V = HMAC(K, V) tmp = tmp || V Update(additional_input) -- this is required even when additional_input was empty return tmp[:N] API for the embedder (each takes a 64-byte state buffer = K || V): nx_drbg_instantiate(state_ptr, entropy_ptr, entropy_len, nonce_ptr, nonce_len, person_ptr, person_len, scratch_ptr) -> i64 nx_drbg_reseed(state_ptr, entropy_ptr, entropy_len, addl_ptr, addl_len, scratch_ptr) -> i64 nx_drbg_generate(state_ptr, out_ptr, out_len, addl_ptr, addl_len, scratch_ptr) -> i64