SafekipediaIn cryptography, CAST-128 (also called CAST5) is a way to keep information safe. It is a symmetric-key block cipher. Many products use it, like some versions of GPG and PGP. The Government of Canada approved it after checking it carefully. This checking was done by the Communications Security Establishment.
The idea for CAST-128 started in 1996. Two people, Carlisle Adams and Stafford Tavares, created it. They used something called the CAST design. There is a related way to keep information safe called CAST-256. It was one of the options for a global safety standard called AES.
CAST-128 works in steps called rounds. There are either 12 or 16 rounds. It handles pieces of data that are 64-bit in size. It can use keys that are between 40 and 128 bits long. The way it works includes special boxes called S-boxes. These boxes mix up bits in different ways and add or subtract numbers. Even though a company called Entrust has a patent on the basic idea, anyone can use CAST-128 for free. This is true for both business and personal use.
This article is a child-friendly adaptation of the Wikipedia article on CAST-128, available under CC BY-SA 4.0.
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