For consideration. Consider adding a comments field to be stored.

[pete4abw]

This would mean a header change, but I am considering adding a comments field. Maybe a max of 64 bytes, but it could contain descriptive information of the compressed file or command line options. The field length would be variable and maybe even bit-packed to save more space. Just a thought for now. Comments?

[pete4abw]

Moving along, this may not involve a header change per se, but would involve either pushing back the initial header group or putting the comments at the end of the file either before or after the checksum block. Also, if we accept a minimum comment size of 16 bytes, we can also encrypt it. The comment format would be a NULL terminated string.A length byte might be needed so that if encrypted, we would know how many bytes to decrypt. No maximum length would need to be defined, although I think 64 bytes should be the max needed.