Changes between Version 7 and Version 8 of NewCaps/WhatCouldGoWrong


Ignore:
Timestamp:
2009-10-11T01:34:51Z (14 years ago)
Author:
davidsarah
Comment:

fix undeletion attacks

Legend:

Unmodified
Added
Removed
Modified
  • NewCaps/WhatCouldGoWrong

    v7 v8  
    1212||9||denial of service||prevent access to servers holding sufficient shares (by controlling some of them, or by attacking them)||anyone||any file||not prevented by crypto||n/a||
    1313||10||cause invalid share to verify||generate (''K1enc'',''Dhash'',''V'') that hash to someone else's (''T'',''U''), and copy their ''S''||anyone||any one file||the hash function's second-pre-image resistance on (''T'',''U'')||2^''t''+''u''^||
    14 ||11||undeletion||undelete a file (making it readable by existing read caps) by restoring its shares||anyone||any one file||assuming a "tombstone" is present on all relevant servers: same as !#10||2^''t''+''u''^||
     14||11||undeletion [footnote 3]||restore the file's shares by controlling the relevant servers||anyone||any one file||not prevented by crypto||n/a||
     15||12||undeletion [footnote 3]||generate matching (''R'',''T'',''U'') for a deleted file||anyone||any one file||the hash function's and cap format's second-pre-image resistance on (''R'',''T'',''U'')||2^''n''+''t''+''u''^||
    1516
    1617where ''k'' = bitlength(''K1''), ''n'' = bitlength(''R''), ''t'' = bitlength(''T''), ''u'' = bitlength(''U''), ''d'' = bitlength(''KD'').
     
    18191. ''shape-shifter immutable file'': creator creates more than one file matching the immutable file readcap
    19202. ''roadblock'': attacker prevents uploader (including repairer) from being able to write a real share into the right storage index; ''speedbump'': attacker adds his bogus share into the list of shares stored under the storage index by the same method; downloader has to download, examine, and discard the bogus (''K1enc'',''Dhash'',''V'')'s until it finds the real one
     213. ''undeletion'': attacker makes a deleted file (for which it need not have had a read cap) accessible at its previous storage index, and readable by previous read caps
    2022
    2123http://allmydata.org/pipermail/tahoe-dev/2009-October/002959.html