mORMot Open Source

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Member

Registered: 2011-01-08

Posts: 9

Plaintext visible in SynLZ compressed data?

plaintext:

Why Use Fossil? There are plenty of open-source version control systems available on the internet these days. What makes Fossil worthy of attention? Bug Tracking And Wiki - In addition to doing distributed version control like Git and Mercurial, Fossil also supports

zip compressed: (fastest)

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     whyusefossil3.txteŽ1nAE¯ò¸JŠ 
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ïË'þPK    a§#@~®Op´   
                  whyusefossil3.txtPK      ?   ã     

synlz compressed:

  Ç Why Use Fossil? There aAwplenty o    f open-source version control sy  └stems available æ╞the internet !ΓQw  ┴days. What makesE
 wort±╢æFatt1Ʊÿ? B   Çug Tracking And Wiki - In addit±ÿ@   to do≥üdistributedlike Git aüfMe   rcurial,F
also supports 

What I say is, on synlz compressed data a few plain text is visible (especially those few from the start of file?) on the top of compressed data. This is a concern for very small text files for which whole plaintext is visible.

In the case of zip compression (even with fastest mode) the plaintext is never visible no matter how small the source file is.

Is there any way you can adopt this in synlz?

ab

Administrator

From: France

Registered: 2010-06-21

Posts: 14,659

Website

Re: Plaintext visible in SynLZ compressed data?

SynLZ is not using any huffman compression, this is why it compresses less than Zip, but it is also the reason why it is so fast.

Zip compressed content is easily uncompressed, so plain text is very easy to retrieve.

There is no intention to add such encryption to SynLZ, since there is no need to. Compression is one matter - encryption another.

If you do not like SynLZ kind of compression, add a cypher layer (just a memory block xor), and your data will be safe.