HQX, BinHex 4.0 Encoded File (.hqx)
The HQX Misc file format
HQX files have been initially created for Apple Mac computers. The data inside the file has undergone compression as well as encoding, resulting in a 7-bit text instead of a 8-bit binary format. The encoding is done using the BinHex 4.0 encoding mechanism. These kinds of files are typically used for file transfer of binary files like documents, images or other multimedia attachments when sending an e-mail. They are used for different means of file transfer on the internet as well.
Technical details of HQX files
HQX files are text files that range from binary to hexadecimal. While BinHex 4.0 is used for encoding in HQX files, RLE is used for the compression. What makes HQX files predestined for file downloads on the internet or sending e-mail attachments is the fact that they couple combine both data and resource fork of the Mac file system to form only one archive. Files with the HQX extension are significantly bigger than the original binary files they were made out of. However, they are not as vulnerable to corruption during the transfer as the original binary files are.