Chapter 243: Sandbox and Whitelist

At 8:40 on Friday morning, the door to the server room on the third floor of the Information Department had not yet opened. Lin Chen leaned against the tiled wall in the corridor, his left foot only lightly touching the ground, his right hand resting by habit on the outside of his knee. At the far end of the hallway, the water dispenser gave off a low hum, and the air carried the mixed smell of disinfectant and dust from old carpeting. He lowered his head and glanced at his watch. The second hand ticked past nine o’clock.

The door opened. Old Wu, a security auditor in a gray work uniform, stepped out holding an access card and a paper registration form. “Engineer Lin? Come in. The administrative office has assigned third-party out-of-band monitoring. The entire session will be screen-recorded today. Just follow the procedure.”

The server room was climate-controlled, with cold air blowing directly at them. Lin Chen inserted the encrypted USB drive into the designated terminal, moving slowly. His left foot had completely lost feeling, and he could maintain his balance only by shifting his weight to the right. The screen lit up, and a command-line window appeared. He entered the load instruction, and the dynamic library began to inject. There was no graphical interface, only scrolling logs and jumping process PIDs.

Old Wu sat down at the workstation beside him and opened a packet capture tool and a memory analyzer. “By the rules, run the standard medical-record dataset once. I’ll be checking memory snapshots, file read-write permissions, and the process tree.” His tone was flat, but his fingers flew across the keyboard. Lin Chen nodded without speaking. He knew exactly what the man was looking for: hard-coded keys, unobfuscated symbol tables, or APIs reading beyond their authority. He had already split the core algorithm into a black box and stripped all debugging information during compilation. All that could be seen now were the hash values of the input data and the JSON structure of the output.

The progress bar reached thirty percent. The log showed the regex matching layer functioning normally and the dynamic backtracking module successfully invoked. Then a warning suddenly popped up on Old Wu’s screen: Process attempting to allocate a large memory block. Lin Chen’s chest tightened, but his expression did not move. That was the compensation algorithm performing preloading, a normal behavior. He had marked the memory threshold in advance in the interface documentation. Old Wu looked up at him, and Lin Chen handed over a printed explanation of resource usage. “Preallocated cache, to prevent blocking under concurrency. It won’t exceed the hospital’s five-hundred-megabyte limit.” Old Wu scanned it once, asked no further questions, and returned his gaze to the monitoring panel.

Second by second, time passed. In the server room, there was only the turning of fans and the tapping of keyboards. Lin Chen’s right leg began to ache. The numbness in his left foot spread upward, like a strip of soaked cotton wrapped around his whole leg. Quietly, he shifted his weight onto his right foot and curled his toes hard inside his shoe, trying to wake up some trace of nerve feedback. It was useless. The pain had long since dulled into a heavy, continuous swelling. He remembered copying code by hand in the library during his sophomore year; after sitting too long, it had felt the same. Back then, he thought enduring it would be enough to graduate. Only now did he understand that enduring it merely meant moving somewhere else to keep enduring. Real-world procedures, like an abacus, recognized only fixed increments, never emotion.

The progress bar reached one hundred percent. The terminal output read: Test dataset processing complete. Time elapsed: 14 minutes 32 seconds. Match rate: 97.8%. No abnormal resident processes. Old Wu closed the packet capture tool and exported the logs. “The procedure is compliant. The memory encryption layer held, and the dynamic library signature matches. I’ll send the report through the internal process this afternoon.” He paused, then added, “For next Wednesday’s demonstration, the hospital will open a real data stream from the ward. You and Zhiyi Cloud will run the same batch of samples, and the results will go directly to the president’s office meeting. Don’t let anything slip.”

Lin Chen pulled out the USB drive; a thin layer of sweat clung to the metal casing. “Understood. Thank you, Engineer Wu.” He got up slowly, setting his right foot down first and dragging his left forward by half a step. When he walked out of the server room, the warmth in the corridor made him shiver. His phone vibrated. A message from Su Man read: Did the certification pass? The server bill expires this afternoon. He replied: Passed. We have 10,400 left in the account. Renew the lease first. Don’t touch the demo environment configuration.

He went to the stairwell and leaned against the fire door, lighting a cigarette. He did not smoke it, only held it between his fingers. The smoke dispersed under the cold fluorescent light. He opened his mobile banking app, and the balance on the screen was glaring. A little over ten thousand. After servers, bandwidth, and Su Man’s base salary, it would last only twenty more days. Next Wednesday’s demonstration was not a technical contest. It was a line between life and death. Zhiyi Cloud had a ready-made medical knowledge graph and a mature implementation team. All they had was this wrapped dynamic library and a pile of compensation logic that still had not fully run through.

His phone vibrated again. This time it was a voice message from his mother, Wang Guiying. He tapped it open. In the background were the sounds of a radio from the village clinic, mixed with distant barking dogs. “Chen, Xiaoman hasn’t had an attack this week. The medicine is almost gone, and there’s still two hundred left from the money you sent last time. Your father’s back hurts, so he didn’t go out to the fields. You’re out there on your own... don’t pinch pennies too hard. Eat on time.” The message lasted only a little over ten seconds. After listening, Lin Chen’s thumb hovered above the screen. In the end, he replied with only one word: Okay. He slipped the phone back into his pocket. By then the cigarette had burned down to the filter. It scorched his fingers. He stubbed it out and tossed it into the trash.

When he returned to the temporary office, Su Man was checking the network topology of the demonstration environment. Printed comparison test plans lay spread across the desk, their corners already curling up. Lin Chen sat down, opened his laptop, and pulled up Wednesday’s demo script. He reorganized the load order of the dynamic library and added a fault-tolerant downgrade switch. If the on-site network fluctuated or the data-stream format changed unexpectedly, the system would automatically switch to offline cache mode and preserve basic functionality from crashing.

“Any movement from Zhiyi Cloud?” he asked.

Su Man shook her head and pushed over a competitive analysis report. “Old Chen leaked a little. They brought two implementation engineers to tune parameters on-site. The hospital president likes seeing results in real time. He doesn’t like waiting. Their interface looks better than ours, and it responds faster too.”

Lin Chen said nothing. On paper, he drew a simple flowchart: Data ingestion → Real-time parsing → Compensation output → Interface display. Between “Real-time parsing” and “Compensation output,” he drew a dotted line and wrote beside it: Latency threshold < 200ms. That was a hard requirement. If they failed to meet it, the demonstration would be a disaster. He picked up the pen again and added another line beneath the dotted divider: Redundant verification: 3 retries, downgrade on failure. Technology had no miracles. It had only parameters and redundancy.

He closed the computer and stood up. His left foot was still numb, but his heartbeat was steady. He walked over to the window and looked down at the parking lot below. That black business van was still there. Zhiyi Cloud’s team seemed to have arrived early to set up in advance. Sunlight struck the paint and reflected a harsh, blinding glare.

His phone screen lit up. It was a text from Old Chen: Update to Wednesday’s demonstration procedure. The hospital has added a temporary item: on-site selection of data from three patients with complex prior medical histories. The system must provide medication conflict warnings. Zhiyi Cloud has already confirmed support. Please be aware.

Lin Chen stared at the line. Medication conflict warnings required a complete drug interaction database and a real-time inference engine. Their compensation algorithm covered only the basic logic and had no external knowledge base connected to it. If they forced it in, it would throw errors. If they did not, they were out.

He sat back down and opened the code editor. The cursor blinked in a blank space. Outside the window, the sky darkened, and the outline of the city blurred in the mist. He knew tonight would be another long one. But this time, encapsulation and obfuscation alone would not be enough. In seventy-two hours, he had to turn that dotted line into a solid one. The sound of typing rose again—dense, restrained, like a march with no route of retreat.