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BinHex, originally short for "binary-to-hexadecimal", is a binary-to-text encoding system that was used on the classic Mac OS for sending binary files through e-mail. Originally a hexadecimal encoding, subsequent versions of BinHex are more similar to uuencode, but combined both "forks" of the Mac file system together along with extended file information. BinHexed files take up more space than the original files, but will not be corrupted by non-"8-bit clean" software. BinHex was originally written in 1981 by Tim Mann for the TRS-80, as a stand-alone version of an encoding scheme originally built into a popular terminal emulator, ST80-III by Lance Micklus. BinHex was used for sending files via major online services such as CompuServe, which were not "8-bit clean" and required ASCII armoring to survive. Not everyone used ST-80, however, so Mann wrote BinHex to allow users of other emulators to use the format. The original ST-80 system worked by converting the binary file contents to hexadecimal numbers, which were themselves encoded as ASCII digits and letters. It then added a newline after every 60 characters. The system became very popular after Mann uploaded it to CompuServe's TRS-80 files area. The system quickly gained the addition of a checksum at the end of every line to check for errors. Bill Stockwell converted that version to the BASIC/S compiler, which ran much faster than Mann's interpreted version. BinHex files of the era were typically given the . Ports soon appeared for other popular platforms of the era, including the Apple II. CompuServe later added support for 8-bit transfers, and the format quickly disappeared. The file upload problem still existed on CompuServe when the Mac was first released in 1984. In April 1984, William Davis ported BinHex to the Mac using Microsoft BASIC to produce a version that was largely identical to the TRS-80 versions of the same era. This version only supported encoding of the "data fork", ignoring the resource fork, which meant it could only be used for data files.

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Related concepts (4)

Binary-to-text encoding

A binary-to-text encoding is encoding of data in plain text. More precisely, it is an encoding of binary data in a sequence of printable characters. These encodings are necessary for transmission of data when the communication channel does not allow binary data (such as email or NNTP) or is not 8-bit clean. PGP documentation () uses the term "ASCII armor" for binary-to-text encoding when referring to Base64.

8-bit clean

8-bit clean is an attribute of computer systems, communication channels, and other devices and software, that handle 8-bit character encodings correctly. Such encoding include the ISO/IEC 8859 series and the UTF-8 encoding of Unicode. Until the early 1990s, many programs and data transmission channels were character-oriented and treated some characters, e.g., ETX, as control characters. Other assumed a stream of seven-bit characters, with values between 0 and 127; for example, the ASCII standard used only seven bits per character, avoiding an 8-bit representation in order to save on data transmission costs.

Base64

In computer programming, Base64 is a group of binary-to-text encoding schemes that represent binary data (more specifically, a sequence of 8-bit bytes) in sequences of 24 bits that can be represented by four 6-bit Base64 digits. As with all binary-to-text encoding schemes, Base64 is designed to carry data stored in binary formats across channels that only reliably support text content. Base64 is particularly prevalent on the World Wide Web where one of its uses is the ability to embed or other binary assets inside textual assets such as HTML and CSS files.