PEA

PEA (Pack, Encrypt, Authenticate) is the "native" format of PeaZip, a free, open-source archiver program which supports a number of other archive formats as well. As its name implies, it has support for encryption and authentication.

Sample files

 * https://telparia.com/fileFormatSamples/archive/peaZip/

Links

 * File format documentation
 * Official site with program download