[tahoe-lafs-trac-stream] [tahoe-lafs] #393: mutable: implement MDMF

[tahoe-lafs]

#393: mutable: implement MDMF
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     Reporter:  warner        |       Owner:  kevan                                                                                                                 
         Type:  enhancement   |      Status:  assigned                                                                                                              
     Priority:  major         |   Milestone:  1.9.0                                                                                                                 
    Component:  code-mutable  |     Version:  1.0.0                                                                                                                 
   Resolution:                |    Keywords:  newcaps performance random-access privacy gsoc mdmf mutable backward-compatibility forward-compatibility review-needed
Launchpad Bug:                |  
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Comment (by kevan):

 Replying to [comment:72 warner]:

 > I can't quite figure out how the MDMF salts are handled, though. I can
 see that they're stored right in front of each data block, but the code
 (at least layout.py, and the parts of publish.py that I've read so far)
 don't make it clear how their validated. There's talk of a "salt hash
 tree", but I can't find any code that manages it. Any hints?

 They're validated alongside the block text that they correspond to. The
 leaves of the block hash tree are of the form {{{hash(salt + block)}}}.
 See around line 854 of mutable/retrieve.py to see that in action.

 (the idea for that is due to your comment:21. Before that, there was a
 salt hash tree. I saw some references to it when I was looking at the code
 to answer your question, which are definitely confusing and should be
 changed.)

-- 
Ticket URL: <http://tahoe-lafs.org/trac/tahoe-lafs/ticket/393#comment:73>
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