UUencode vs. UUdecode vs. yEnc

Getting those binary files onto newsgroups - (aka Unix-to-Unix encode)

First, let's start with a definition of UUencode/UUdecode: "the conversion of a binary file (e.g. movies, MP3, pictures, software, etc.) to/from an ASCII (text) file so it can be sent as an attachment via email or posted/downloaded to/from a newsgroup. UUencode converts non-text files (binary files) as text so that they can be included in a mail messages and newsgroup posts. When the message is received, the recipient, or their newsreader application, runs UUdecode to convert it back to its original state."

In essence, software (usually included within the newsreader) is used to transform binary files into text characters and vice-versa. You can tell you're looking at an UUencoded post if it starts with the line, "begin 644 somefilename.ext", followed by a jumbled series of characters.

The problem with UUencoding is it significantly increases the filesize (as compared to the original) when posted to Usenet. Some say around 35% increase, thus explaining why Usenet traffic nowadays is approximately 500-1000GB per day.

A new way to encode postings - yEnc

yEnc is a new encoding method which purportedly offers better transmission for binaries on Usenet. Posts subjects often (but not always) have "yEnc" spelled out, which helps readers determine the type of binaries post.

The problem with this new encoding method is not surprising -- many newsreaders don't support yEnc, thus making it difficult to decode yEnc encoded files (without an additional application). Fortunately, the more popular newsreader applications have added support for yEnc into their software. See a list of newsreaders that support yEnc.

To find out more about yEnc, visit their homepage.

Other encoding methods

You're best bet, if you're going to be posting binaries, is to use UUencoding. It's been around for years, almost all newsreaders support encoding/decoding, and is the most common form used by folks posting to Usenet newsgroups.

Other less common encoding methods for Usenet posts are BASE64, BinHex, Quoted Printable. See their technical definitions below:

Base64 - encoding for binary data consisting only of 64 encoding characters (A-Z, a-z, 0-9, +, /) that are a subset of US-ASCII.

BinHex (BINary HEXadecimal) - another method for converting non-text files (non-ASCII) into ASCII.

Quoted Printable - encoding largely consisting of octets that correspond to printable characters in the ASCII character set. It encodes the data in such a way that the resulting octets are unlikely to be modified when posted. If the data being encoded are mostly ASCII text, the encoded form of the data remains largely recognizable by humans. A body which is entirely ASCII may also be encoded in Quoted-Printable to ensure the integrity of the data should the message pass through a character- translating, and/or line-wrapping gateway.