Skipjack (cipher)

In cryptography, Skipjack is a block cipher—an algorithm for encryption—developed by the U.S. National Security Agency (NSA). A block cipher is a way to scramble information so that only someone with the right key can read it again.

Skipjack was created to help protect secret data by turning it into a form that looks random and unreadable.

At first, the details about how Skipjack worked were kept secret, which means only certain people were allowed to know. This made it a classified piece of technology. It was planned to be used in a special computer chip called the Clipper chip.

Later on, the information about Skipjack was made public. This allowed everyone to learn about how the cipher worked and study its strengths and weaknesses. Skipjack became an important example in the study of encryption.

History of Skipjack

Skipjack was created to encrypt information for the U.S. government. It was meant to be used in a special chip called the Clipper chip. The way Skipjack worked was kept secret at first, which made many people uneasy.

In 1998, the government decided to make Skipjack public. Before that, experts looked at how Skipjack worked and found it to be safe and reliable. Skipjack was developed by the U.S. National Security Agency and used ideas from older encryption methods. By 2016, Skipjack was no longer approved for government use.

Description

Skipjack is a special kind of code used to hide information, called a block cipher. It uses an 80-bit key to lock and unlock 64-bit pieces of data. This method has 32 steps to keep the information safe, and it was once planned to be used in secure phones.

Cryptanalysis

Researchers learned how to break some parts of the Skipjack cipher soon after it was shared. They showed ways to attack most of the cipher's steps, but these were not much faster than trying every possible key one by one.

Later, someone said the whole cipher could be broken. But in 2009, it was made clear that no good way to break all 32 steps of Skipjack was known at that time.

In pop culture

The algorithm named Skipjack appears in the back-story of Dan Brown's 1998 novel Digital Fortress. In the story, Skipjack is shown as a new way to keep messages safe online, but it has a secret way for the NSA to read those messages.

In the video game change Dystopia for Half-Life 2, an "encryption" program uses Skipjack with another method called Blowfish to keep information safe in a pretend world.