What is encryption and decryption?

Encryption/decryption is particularly important in wireless communications. This is for the reason that wireless circuits are easier to "tap" than their hard-wired counterparts. On the other hand, encryption/decryption is a good plan when working whichever kind of sensitive transaction, like a credit-card purchase online, or the conversation of a company secret between different departments in the organization. The stronger the cipher -- that is, the harder it is for illegal people to break it -- the better, on the whole. Conversely, as the strength of encryption/decryption increases, therefore does the cost.