Re: unzip and password protected archive

[Thomas Klausner <wiz%NetBSD.org@localhost>]

On Sun, Mar 07, 2010 at 11:08:27AM +0100, Joerg Sonnenberger wrote:
> I wouldn't find out in 10min whether
> zip sets the bits in the pre-file header or only in the central
> directory. The former would be a requirement of being able to implement
> this in any sane way though.

The requirements for old-style encryption seem to be:
"version needed to extract": at least 2.0 (encoded as value 20, i.e. 0x14)
"general purpose bit flag": bit 0 set ("strong" crypto also sets bit
6, but then the version needs to be at least 5.0)
The description for these bytes doesn't say that they may be different
in the central directory entry, so I assume they must be set in the
local header if an entry is encrypted.
 Thomas