41 Bytes from the Future

Two different pieces of equipment showed the same 41 bytes. One was Im Doyun's forensic terminal, the other was Minchae's offline laptop. The screen brightness and font were different, but the number in the length field was the same. 41. Looking at that number, I thought of the offline second hand in front of the oxygen valve. The same number isn't an answer. It's a starting point for comparison.

"We didn't sync them," Minchae said first. "My device has the network off, and I cut the file straight from Seojin's original audio. The hash is right here."

Seojin picked it up right away. "The original audio file was created at the hospital's back gate, and all three copies have the same creation time and hash. It's not an edited version."

Im Doyun didn't take either of them at their word right away. "The time each file was moved onto the other person's device."

"I read it first, and Seojin called out the hash."

"Record the order."

Minchae closed her mouth and wrote the order down again. Nobody was asking to be trusted anymore. They were building an order that could be trusted.

The forensics room was a spot temporarily cleared out of the hospital's basement server room. Old LAN cables were bundled by color on the wall, and a moisture proof mat covered the floor. Im Doyun had physically unplugged the institutional terminal from the network. The end of the cable sat on top of the desk. That was more convincing than any statement that it hadn't been connected.

He'd taped off three zones on the desk. Original, verified copy, and releasable copy. In the original zone sat an envelope holding a storage device image pulled from a seized phone. In the verified copy zone were two USB drives with only hash values written on them. The releasable copy zone was empty. Seojin looked at the empty space and asked.

"Why isn't there a releasable copy yet?"

"The scope of release hasn't been decided."

"Who decides that scope?"

"The evidence preservation lead, the holder of the original reporting material, and the rescue site lead can each raise objections."

Seojin didn't look happy about it, but she nodded. Releasing it right now could blow Gwon Taemuk's name wide open. But if the original got seized, the release would just be shouting into the air while the evidence disappeared. She knew the difference.

Minchae didn't plug her offline laptop's power cord into the wall outlet. "If the power here shares a line with the institutional network, noise could get in. I'll run it on battery only."

"Battery time."

"Nineteen percent. I can't run it long. So I won't decrypt the whole thing."

That limit set the pace for the whole procedure. Instead of revealing everything, we decided to fix in place only what we could reveal first.

"Separating the header," the technician said.

Short lines appeared on the screen. There was only one line of plaintext. The dead do not create branches. The rest looked like fragments resembling a device ID, a timestamp, a checksum. The trailing 8 bytes couldn't be interpreted. When Minchae reached to touch that part, Im Doyun stopped her.

"Original preservation comes first."

"I was only going to read it."

"Even reading leaves traces."

Minchae pulled her hand back. "So no capture either?"

"Capture on a separate copy only."

Seojin said in a low voice. "Nice. Finally someone's saying to make the copy first."

The original was sealed once more. The technician didn't work directly from the original image. Instead he made a verified copy and cross checked the hash value against it. Minchae wrote that value down by hand in her notebook. Handwriting was slow, but it survived even if the screen went dark. Seojin read the same number aloud and recorded it.

"Is there a reason you're reading the number aloud?" Im Doyun asked.

"Even if the filename changes later, I can check whether the sound, the paper, and the screen all match."

"Good. Just don't read the original text."

Seojin closed her lips for a moment. Broadcasting was her trade, and the moment she read something, the urge to release it kicked in. So not reading was harder for her than for anyone. She only read the numbers. She didn't read the sentence. The fact that I already knew that sentence didn't mean everyone was free to handle it carelessly.

Minchae almost laughed, then stopped. Jang Yura was standing at the door of the forensics room. She wasn't taking part in the investigation. Instead she was keeping people in the hallway from coming in. Unlike the rescue site, this time her job was guarding a door.

When the timestamp came apart, the technician's hand stopped.

"It's twenty seven days after now."

Im Doyun asked. "Possibility of system clock corruption."

"There is one. But this value isn't network time, it's a value inside the block itself. Someone wrote it, or the device generated it, or it was synthesized."

"Which of the three can be confirmed."

"None."

I looked at the number. Twenty seven days. It matched the return interval. That alone didn't mean I could call it the real future. Numbers can be fit into place. Someone might have written this value in to manipulate me. But I couldn't dismiss the fact that it sat in the same block as a device ID that hadn't even been installed yet.

"It matches the return interval," I said.

Im Doyun asked right away. "The basis for that statement."

"My memory."

"Anything besides memory."

"Nothing."

"Then how does that go into the investigation record?"

Before answering, I looked at my notebook. The old me used to lock things in too fast in moments like this. Locking something in moves people, but when it turns out wrong, it causes damage that can't be undone.

"According to Han Igyeom's statement, matches the return interval. Objective physical evidence unconfirmed."

Im Doyun wrote it down exactly as it was. It wasn't the sentence I wanted, but it was the sentence that was needed. Seojin copied the same sentence into her own notebook. Minchae put the value twenty seven days into a separate box and wrote three question marks beside it.

"Is there any way to tell whether it's a real future timestamp or a synthesized value?" Jang Yura asked from the doorway.

The technician answered. "Not right now. We'd need the device's original log."

"If the device hasn't even been installed yet."

"That's exactly why we're stuck."

Being stuck was, if anything, what steadied the room. Admitting where you're stuck lets you find another way. If you don't say you don't know, every path looks like it's already open.

"7C." Minchae said, then immediately covered her mouth.

There was a short notation on one side of the header. `7C`. Nobody knew what it meant. It resembled a sequence name I'd glimpsed in passing at the end of the original timeline, but saying that now would bundle too much into a single line.

"Just what you read." Im Doyun said.

Minchae corrected herself. "There's a character string 7C in the header. Meaning unknown."

Seojin wrote that down in her notebook exactly as said. Meaning unknown. Two lines were drawn under her handwriting. That kind of statement is the first thing cut when something goes public. So she underlined it first.

Minchae didn't attach any explanation next to `7C`. Her hand moved once, but she erased it.

"Why did you erase it?" Im Doyun asked.

"I was about to act like I knew something."

"Content."

"I was going to write that it resembled a code I saw in the original timeline, but that's not accurate."

I looked at Minchae. She shouldn't try to prove my memory for me. A child's goodwill can ruin evidence. Minchae seemed to know that too, because she set her pen down.

"Resemblance doesn't get recorded." Im Doyun said.

"What about Han Igyeom's reaction, then?" Seojin asked.

"Observation record only. No assigning meaning."

Even my own reaction could become evidence. I didn't like that fact, but this time I accepted the discomfort.

Right then a warning popped up on the institutional terminal. Remote preservation policy update. Original scheduled for deletion. The technician reached out immediately, but Im Doyun was faster. He didn't press the power button. Instead he physically disconnected the storage device's connector. There was a small metallic click.

The warning window didn't close. It stayed on screen even after the connection was cut. The scheduled deletion time was ninety seconds after the current time. Whether someone had pressed it manually or the policy had come down automatically, there was no way to tell from the screen alone. But the approval field wasn't empty.

"Is the printer connected to the network too?" Seojin asked.

The technician shook his head. "It's local."

"Then print it."

Im Doyun gave the same order. "Print it, and photograph the screen. Photograph the storage device in its disconnected state. Photograph the cable's position."

Jang Yura shut the door. "From now on, access to this room is restricted."

"Do you have the authority for that?" the technician asked.

"I have preservation authority over the rescue site. If people crowd in, this stops being evidence and becomes an accident."

Im Doyun didn't argue. "Record the reason for the access restriction."

The people in this room were doing the same thing for different reasons. Im Doyun to protect the evidence, Seojin to keep the original from being taken away, Yura to keep people from getting hurt, Minchae to avoid saying anything wrong. In the middle of it I was trying to see where the sentence had come from. Our purposes were different, but for that moment, our hands were moving in the same direction.

"Evidence sealing first. Block the remote command."

"It's a policy from above." the technician said.

"Evidence preservation procedure comes first. Print the command's original text."

The technician hesitated. Im Doyun didn't raise his voice. "I'm the one responsible here. Print it."

The printer moved slowly. Everyone watched the screen until the paper came out. The deletion command looked like an automated system sentence. But there was a person's name in the approval field.

National Continuity Bureau Chief Gwon Taemuk.

The moment the name appeared, the air in the room changed. Gwon Taemuk had never once appeared in front of me. And yet his approval signature had tried to erase my evidence before I even got to him. Not the face of a villain, but an administrative signature.

I started to imagine Gwon Taemuk's face, then stopped. Attaching a face makes a story easier. What we had, for now, wasn't a face. Only an approval phrase, a title, a timestamp, and a deletion target.

"Can we assume this approver knew the contents of the packet?" Jang Yura asked.

Im Doyun answered while sliding the printout into an envelope. "We can't assume that."

"Then what can we know?"

"That an attempt was made to delete this original using this approval authority."

Seojin said. "Whether the approver was the actual person who entered it is also unconfirmed."

"Unconfirmed."

I held on to that word. The name Gwon Taemuk carried plenty of weight, but the heavier a name is, the more careful we need to be. A big name pulls small evidence toward itself. And in the process, the small evidence loses the actual scope of what it's saying.

Seojin asked. "Can we broadcast this?"

Im Doyun didn't answer right away. "Releasing it now could speed up an attempt to seize the original."

"Record the reason for holding it back."

"Record it."

Minchae kept the offline laptop screen open and checked the battery level. Nineteen percent. "I can make two copies. One with just the hash, one with the original text."

"Seal the original text copy," Im Doyun said. "Cross verify with the hash copy."

Seojin nodded. "That should be enough to preserve it before release."

They didn't make a third copy. Minchae's battery had dropped to eleven percent, and there was no reason to increase the number of accesses to the original any further. Instead, Seojin wrote out the sentences that could be made public separately. `41 byte block exists`, `one line of plaintext`, `timestamp 27 days after now`, `7C header`, `deletion attempt approval field: Gwon Taemuk`. She marked the unresolved trailing value and the device ID details as held back from release.

"Why leave out the device ID?" Minchae asked.

"If we release it now, someone could put together a fake list of devices. Or move the real device somewhere else."

"Then people won't be able to believe it."

"Preserving the original comes before making people believe it."

Minchae didn't answer. Saying preservation comes before belief was a boring thing to say, whether you were a kid or an adult. But this case couldn't afford to be interesting.

I split my notebook into two lines. Packet: 41 bytes, one line of plaintext, timestamp 27 days after now, 7C header, trailing value unresolved. Yun Seola's signature: separate. I deliberately left space between the two lines. Connect them too hastily, and all the evidence starts to look like it points to one mastermind. Not yet.

Jang Yura came in from the hallway. "A tip came in from near the sluice gate annex. They say a device code similar to the one in the hospital's red door log was used."

"Source."

Seojin answered. "One facility subcontractor technician, one former bureau contract worker. No original yet."

"Then it's unconfirmed."

Im Doyun slid the printed deletion command into an envelope. "We're going to check it out. But Han Igyeom stays a suspect."

"Going to the site in handcuffs?"

"We record flight risk and on site necessity together."

Jang Yura said. "If rescuing people on site comes first, the placement of the handcuffs is a condition too."

Im Doyun looked at my wrists. "Front handcuffs stay on. No handling anything on site."

I nodded. Even without handling anything, I could still look. For now, I had to start over from looking.

On her way out, Seojin glanced up once at the forensics room light. "Request preservation of the CCTV originals here too."

Im Doyun looked at the technician.

"The server room CCTV runs on a 24 hour rolling storage."

"Preserve it immediately." Im Doyun said.

Seojin added in a low voice. "So no one can later say nothing happened in this room."

Nobody laughed at that. From now on we had to deal not just with the case itself, but with the way the case was being erased. The fact that we didn't know what the packet meant hadn't changed, but now there was also the fact that someone was trying to erase that not knowing.

The printer's last line finally came all the way out. Deletion approver. Gwon Taemuk. A sealing sticker was placed under that name.