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A '''binary to text encoding''' is [[Character encoding|encoding]] of data in [[plain text]]. More precisely, it is an encoding of [[binary and text files|binary data]] in a sequence of [[ASCII]] printable characters. These encodings are necessary for transmission of data when the channel or the protocol only allows ASCII printable characters, such as [[e-mail]] or [[usenet]]. [[PGP]] documentation uses the term ''ASCII Armor'' for binary to text encoding when referring to [[Radix-64]].
==Description==
The ASCII text-encoding standard uses 128 unique values (
▲The ASCII text-encoding standard uses 128 unique values (0–127) to represent the alphabetic, numeric, and punctuation characters commonly used in the [[English language]], plus a selection of 'control codes' which do not represent printable characters. For example, the capital letter ''A'' is ASCII character 65, the numeral ''2'' is ASCII 50, the character ''}'' is ASCII 125, and the metacharacter ''carriage return'' is ASCII 13. Systems based on ASCII use seven bits to represent these values digitally.
By contrast, most computers store data in memory organised in eight-bit [[byte]]s, and, in the case of machine-executable code and non-textual data formats where maximum storage density is desirable, use the full range of 256 possible values in each eight-bit byte. Many computer programs came to rely on this distinction between seven-bit ''text'' and eight-bit ''binary'' data, and would not function properly if non-ASCII characters appeared in data that was expected to include only ASCII text. For example, the value of the eighth bit might not be preserved, or the program might interpret a byte value above 127 as a flag telling it to perform some function.
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==Encoding standards==
The most used forms of binary to text encodings are:
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