The Unbreakable Code

Imagine solving a complex equation without knowing the format of the final answer: you will never know when you have arrived at a solution! I read this cool tech-fiction by Dan Brown called 'The Digital Fortress'. It's among his very old works that I came across in one of the local libraries. It is based on the story of a code-breaking machine called TRANSLTR hosted by the National Security Agency of the United States for decrypting messages to safeguard national integrity. This machine makes it possible to break every complex code and makes critical information accessible. But the catch over here is that to decode information that might be a potential threat to the US, TRANSLTR has access to several other transactions as well. This means that regular communications like emails and messages between ordinary citizens are also decoded. US citizens are unaware of TRANSLTR's existence. Although for the NSA this is a routine, many cryptographers, including a few of the NSA's employees, consider this as a breach of privacy. Ensei Takando, a former NSA employee resolves to reveal TRANSLTR to the world by threatening NSA. He pursues the NSA into believing the existence of a rotating cleartext code he developed. According to the fiction, rotating cleartext is an algorithm that in addition to encrypting, shifts the decrypted cleartext over a time-variant. This is a fictional concept according to which the computer will never locate a recognizable pattern to break the code even though it might arrive at the right key in between the shifting letters.

The NSA's deputy director is persuaded to let the code into TRANSLTR and bypass the virus filters. He works on a master plan of creating a back door to the so-called digital fortress code after getting hold of the pass key (that only Ensei Takando and his partner N Dakota possess). After doing so he would reveal TRANSLTR to the world and falsely declare to the public that digital fortress is an unbreakable code. This code when connected to a computer installed on a chip would make TRANSLTR difficult to intrude on peoples' communications. But actually, the NSA would have access to all the communications through the code's back door.

However, soon it is reveled that N Dakota never existed. It is just an anagram of Ensie Takando. He used another email ID to mislead the NSA into the conversations between himself and the virtual N Dakota. The original pass key for Digital Fortress is only with Ensie and is engraved on his ring. Ensie is soon killed and NSA get hold of the ring. 

The end is slightly disappointing where its is revealed that the code isn't a rotating cleartext but a computer worm that destroys TRANSLTR. However, in order to save the databank that contains critical security information, the pass key has to be entered. It is engraved on the ring in the following format.

 PFEESESNRETMPFHAIRWEOOIGMEENNRMAENETSHASDCNSIIAAIEER BRNKFBLELODI

These alphabets when arranged in the groups of four, give the following pattern

FEE SESN RETM MFHA IRWE OOIG MEEN NRMA ENET SHAS DCNS IIAA IEER BRNK FBLE LODI

This is a perfect square 64, when arranged in 8 rows of 8 gives a Caeser box. Julius Caeser would send messages by arranging random letters which had to be decrypted by arranging them in a square and reading the alphabets from top to bottom.

After reading from top to bottom we get the following sentence

PRIME DIFFERENCE BETWEEN ELEMENTS RESPONSIBLE FOR HIROSHIMA AND NAGASAKI

This turns out to be the difference in the atomic numbers of the two elements used in the bombs used on Hiroshima and Nagasaki: Uranium-235 and Uranium-238: 238-235 = 3. The pass key is 3. It is entered just in time to save the database. 

The book contains a lot of drama based on the emotional dynamics of complex relationships between people, which is slightly out of place in a book based on a logical sequence. While studying prime numbers at school, I never knew they had such wide-ranging applications. They are everywhere: in encrypting messages, online transactions, and quantum computing technologies. 

©Neha Kanase