Are ZLIB and ZLIB2 no longer supported in GnuPG?

Werner Koch wk at
Sun Feb 28 09:54:12 CET 2016

On Fri, 26 Feb 2016 20:23, anthony at said:

> options in my .conf file. Specifically, it told me that ZLIB and ZLIB2
> weren't supported as compression algos.

You need to install a zlib development package before building GnuPG so
that it can add support for this.  You may also want to add bzlib2

On Debian based system:  apt-get install zlib1g-dev  libbz2-dev

> compile flag that I didn't pass it? If they aren't supported, are there
> any security or usability implications to only using ZIP for compression?

As with most compression algorithms you are subject to DoS because it is
possible to create very small compressed file which will expand into a
huge output.  (Use --max-output to mitigate such attacks.)



Die Gedanken sind frei.  Ausnahmen regelt ein Bundesgesetz.

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