Binary-to-text encoding

PGP documentation (RFC 4880) uses the term "ASCII armor" for binary-to-text encoding when referring to Base64.

Those communication protocols may only be 7-bit safe (and within that avoid certain ASCII control codes), and may require line breaks at certain maximum intervals, and may not maintain whitespace.

It is often desirable, however, to be able to send non-textual data through text-based systems, such as when one might attach an image file to an e-mail message.

Many programs perform this conversion to allow for data-transport, such as PGP and GNU Privacy Guard.

For example: By using a binary-to-text encoding on messages that are already plain text, then decoding on the other end, one can make such systems appear to be completely transparent.

For example, the ViewState component of ASP.NET uses base64 encoding to safely transmit text via HTTP POST, in order to avoid delimiter collision.

A series of small English words is easier for humans to read, remember, and type in than decimal or other binary-to-text encoding systems.

Some older and today uncommon formats include BOO, BTOA, and USR encoding.