“What’s the difference? You’re going to tell me anyway, right?”

A patient sigh. “It means ‘hidden writing,’” she said. “That’s what it means in the Greek, literally.”

“Okay…”

“But in this case it means information that’s concealed in pictures. Or music files.”

“And how do you hide a message in a picture – or a song?”

The Smithie in her smirked. “Digital information is just digital information,” she revealed. “A graphic file or an audio file is still composed of bits and bytes, just like a text file. With a program like Stegorama – and there are dozens of them – you can embed information in the image. You could put two photographs of the same thing, taken from the same angle, side by side, and they’d look identical. But the one containing encrypted data is actually a compressed version of the original. You just can’t see the difference without a microscope.”

Spagnola was interested now. “Realllly!”

“Yes,” Humvee said. “Really. The Steg programs decide which parts of the image are least important to its visual integrity, and that’s where the cipher is embedded. It’s hidden in the boring bits, so to speak. In the background, or whatever.”

“And Simoni was doing this?”

She shrugged. “He had the program. So we sent his computer to the States. They were working their way through the graphic files. He had a couple of hundred JPEG files in the Pictures folder. So the search was glacial. But they found what they were looking for-”

“Messages?”

“Statistical deviations in the byte counts. They could tell there were too many bytes in the files, which is a dead giveaway.” She paused. “But, yes,” she said in a grudging voice, “there were ‘messages’ in the pictures. Encrypted messages. NSA’s working on the decrypts now.”

Spagnola frowned in thought. “So… I don’t get it. Where were the pictures going?”

Humvee pursed her lips. Finally, she said, “Remember the book they found?”

“In Simoni’s apartment.”

“Exactly.”

Spagnola nodded. “Yeah, it was a Koran or something. He had it wrapped up like it was a bomb.”

“And he was mailing it to a bookstore in Boston,” Humvee reminded him.

“Right.” Suddenly, his eyes widened as if a lightbulb had gone off inside his head. “So he was communicating with someone in the bookstore!”

Humvee shook her head. “No, the bookstore owner didn’t know squat. The Bureau sent a couple of agents to interview him – and the guy is exactly what he seems to be: someone who buys old books.”

“Then what’s the point?” Spagnola asked, frustrated that he had to tease the information out of this great block of feminine pulchritude.

“The Bureau asked him how he came to buy this particular book, and guess what he tells them? He tells them he found it on eBay.” She waited for Spagnola to connect the dots.

“You mean-”

She nodded. “Simoni was posting his pictures on eBay auctions, so anyone could access them. If you had the Steg program and knew where to look, you could find the messages, no problem.”

“And the books?”

“Forget the books,” Humvee told him. “The only reason Simoni delivered the books was to back up his cover. Otherwise, eBay would have bounced him.”

Spagnola blinked a couple of times. Finally, he said, “I see.” And he did. It was brilliant. Simoni was using eBay as if it were a dead-drop. It was al-Qaeda 2.0.

“So the agent,” he said, “the guy Simoni was talking to, he didn’t have to do bupkes.”

Humvee shook her head. “EBay was just a bulletin board. All the agent needed to do was to plug ‘Akmed’s Books’ into the Search bar, and wait for the page to pop up. If he had Stegorama on his computer, and remembered the password, extracting the message was a cinch. Of course, if it was encrypted, he’d have to decode it. And, unfortunately, that seems to be the case with the messages they’ve found. They’re all enciphered.”

“So we don’t know what they say.”

“Not yet.”

“How long before they crack it?”

Humvee shrugged. “It’s al-Qaeda, so they put us at the front of the queue, but who knows? Maybe tomorrow. Maybe next week, maybe-”

“What about tracking the people who went to the website?”

“EBay?!”

“Not all of eBay. Just the pages with Simoni’s pictures.”

Humvee stared at him as if he had pencils in his nostrils.

“You go to a website,” Spagnola insisted, “you leave footprints. I know that much.”

Humvee patronized him with a smile. “You mean, cookies?”

“Yeah. Cookies.”

Humvee shook her head. “The website might leave a cookie on your computer, but your computer wouldn’t leave a cookie on the website.” She paused to let this sink in. “If we had a suspect, we could look at his computer to see if he’d gone to a particular site… maybe. But I don’t think eBay’s servers keep track of everyone who accesses it.”

“How do you know?” Spagnola asked.

“I don’t. But even if they did, they wouldn’t keep track of everyone who visits every auction, especially if they don’t bid. And why would Simoni’s people bid? They probably have their own Korans already.”

“But you’ll check,” Spagnola insisted.

Humvee shrugged. “Sure,” she said. “I’ll check.”

Spagnola crumpled the can of Coke Light and tossed it into his wastebasket. He was just beginning to realize that Humvee had screwed him. This was a high-profile operation and she hadn’t bothered to tell him anything until they hit a dead end, and sent the computer to NSA. Of course, there would be a copy of her brief on the desk of the chief of station, and the old man would know that this was all Humvee’s work and initiative, not Spagnola’s. Anger rose in his chest. He could feel his face burning.

“Why didn’t you tell me about this?”

“You mean-”

“The steganography! The fact that Simoni was using eBay.” His hands flew up. “Everything.”

“I’m sorry,” she said, without a hint of regret. “It just didn’t seem like your kind of thing.”

“My kind of thing?”

He chewed her out for two minutes. Who did she think she was? He was her boss! He couldn’t believe she’d taken it on herself to contact NSA! What was she thinking?

She flushed, but she couldn’t hide a look of triumph.

Now he’d have to stay in town, Spagnola thought, waiting for the decrypts. Visions of his escape to the slopes with his wife and daughter faded.

“So,” he said, “we’re on hold.”

“More or less.”

“I was hoping to get away for the weekend.”

A soft tsk fell from her lips. “Well,” she said, “it’s only Wednesday. And let’s face it, NSA has its own fish to fry. I’d be very surprised if we hear anything at all before next week.”

Spagnola looked hopeful. “Really?”

“Probably the end of next week.”

“Okay,” Spagnola decided, feeling better about it all. “Just make sure you keep me in the loop, okay?”

“Absolutely.”

The NSA decrypts were hand-delivered to Madison Logan’s office on Friday afternoon, about an hour after lunch. Her first instinct was to take them directly to Spagnola’s, but then she remembered what he’d said about getting away for the weekend. So she put the packet, unopened, in her personal safe, and grabbed her coat. On her way out, she asked the third-floor receptionist to let Mr. Spagnola know that she’d left for a dental appointment – a root canal – and would probably not be back until Monday.

In fact, she went shopping in the Uhland Passage, where there was an upscale boutique that specialized in couture for “plus-size” women. At four o’clock, she called the office to see if there were any messages.

“Mr. Spagnola was asking for you,” the receptionist told her, “but then he left. He said it wasn’t urgent.”

Hurrying back to the office, she went to her safe and retrieved the package of decrypts. A quick glance told her they were dynamite. Picking up the phone, she dialed Spagnola’s office. After the fifth ring, she left a message. “This is Madison,” she said. “The decrypts we were talking about just came in. I think they’re important. If you’ll get back to me, I’ll bring them right over. Otherwise… I’m not quite sure what to do.”