This is a 32-bit RISC OS build of the Zip utility from Andrew Wingate:

  http://www.sparse.net/csa.html

I don't think he's put the sources up on his site, but they can be found
here:

  http://www.info-zip.org/

Andrew says: "They were compiled using the current GCC SDK and support
encryption/decryption and the Extended TimeStamp Field. They cope very well
with moving C sources to/from other systems, thanks to Unzip$Exts, Zip$Exts
and the -/ command-line switch."
