However, when situations allow, the escape sequences "~{" and "~}" sometimes surround characters represented in EUC-CN; this alternative use allows Chinese to be readable either with the help of HZ decoder software, or with a system that understands EUC-CN.
The first HZ encoder and decoder were written in 1989 by the code's inventor for the Unix operating system.
[4] The hztty program, also for the Unix operating system, was also among the first and one of the most popular HZ decoders.
It deviates from the specification in that it will display the escape sequences (i.e., "~{" and "~}"), and it does not treat "~~" and "~" followed by a newline specially.
Because of its escape sequences, and furthermore because its escape delimiters are printable characters in ASCII, it is fairly easy to construct attack byte sequences that round-trip from HZ to Unicode and back.