yEnc is an encoding method designed for sending files over Usenet and e-mail protocols. It converts binary data files into an 8-bit extended ASCII format, which is recognized by e-mail programs and news readers.

yEnc serves a similar purpose as other encoding methods, such as Base-64 and Uuencode (which produces .UUE files). However, it creates smaller file sizes and includes a CRC checksum that is used to verify that the entire file has been transferred successfully.