lkml.org 
[lkml]   [2004]   [Apr]   [14]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
    /
    Date
    From
    SubjectRe: Using compression before encryption in device-mapper
    On Wed, Apr 14, 2004 at 01:44:33PM +0100, Paulo Marques wrote:
    > Guillaume Lac?te wrote:
    >
    > >>>Oops ! I thought it was possible to guarantee with the Huffman encoding
    > >>>(which is more basic than Lempev-Zif) that the compressed data use no
    > >>>more than 1 bit for every byte (i.e. 12,5% more space).
    >
    > WTF??
    >
    > Zlib gives a maximum increase of 0.1% + 12 bytes (from the zlib manual),
    > which for a 512 block will be a 2.4% guaranteed increase.
    >
    > I think that zlib already does the "if this is bigger than original, just
    > mark the block type as uncompressed" algorithm internally, so the increase
    > is minimal in the worst case.

    It is my impression that meta-data is exactly what he wants to avoid as it would
    provide known data for crackers
    -
    To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
    the body of a message to majordomo@vger.kernel.org
    More majordomo info at http://vger.kernel.org/majordomo-info.html
    Please read the FAQ at http://www.tux.org/lkml/

    \
     
     \ /
      Last update: 2005-03-22 14:02    [W:0.021 / U:0.176 seconds]
    ©2003-2016 Jasper Spaans. hosted at Digital OceanAdvertise on this site