base64 Encoding
Consider this problem.
Imagine you have some binary data but you need to send it over a network which only allows 7 bits of information. i.e. the data needs to be encoded in the range 0-127. But your source data is in the range of 8 bits - i.e. 0-255.
Is it possible to derive an algorithm which can re-encode the data into this range so that you can send it over the network? Then the receiver can use another algorithm to de-encode the data when it received.
This was the problem faced in the early days of electronic mail (email) which was sent over a 7 bit transport.
There are many ways of solving this problem. One of them is called base64 encoding. For now I will just refer you to wikipedia to learn more about how this encoding works.
base64 is used for many applications including HTTP basic authentication.