[Chapter 4] American Bletchley

Chapter 4: Clock Ticks and CPU Cycles

The FPGA’s lights began to blink on, then started blinking so fast that to their eyes it just appeared like the they were dim. On Terry’s screen, cryptographic outputs were starting to turn into clusters of more repetitive patterns.

“It’s working,” Terry said.

Soon they began to see plain text. They were fragments at first, just a few words. But as the FPGA managed to decrypt more of the messages, they were able to put together a narrative.

confirm phase one supplies are received - package for grand hall delivery eta 0800 friday

old iron horse sleeps deep - minimal guard north tunnel access

target is main concourse - ensure all trigger simultaneous - whistle at 0815 - rush hour

The two of them shared a look. They wanted to celebrate their successful decryption, but they were terrified by the conclusion.

“This is happening soon. In a day. Grand Hall… Main Concourse… they’re planning a major attack at multiple points.”

The FPGA decryption wasn’t done. It began to display additional messages it had churned through. They got more information on the specific explosive devices being planted, estimates on the number of lives lost, and several codenames for others who were involved in this terrorist plot. It seemed real and serious.

“We have less than 24 hours,” David said as he was debriefed. “I need to bring this report to the FBI Baltimore field office and then to Homeland Security.”