tahoe-lafs/trac-2024-07-25
2
0
Issues 1.1k Wiki Activity

add attack on verify cap 

[Imported from Trac: page NewCaps/WhatCouldGoWrong, version 7]
davidsarah 2009-10-11 01:18:11 +00:00
parent c7d7682951
commit e541673fba
1 changed files with 6 additions and 4 deletions
Show stats Download patch file Download diff file Expand all files Collapse all files

10
NewCaps/WhatCouldGoWrong.md

@ -9,11 +9,13 @@ This is about What Could Go Wrong with the "Elk Point 2" immutable file caps: <h
|4|roadblock or speedbump [2]footnote|generate (*K1enc*,*Dhash*,*V*) that hash to someone else's *T*, and copy their *S*|anyone|any one file|the hash function's and cap format's collision resistance on *T*|2^*t*^| |4|roadblock or speedbump [2]footnote|generate (*K1enc*,*Dhash*,*V*) that hash to someone else's *T*, and copy their *S*|anyone|any one file|the hash function's and cap format's collision resistance on *T*|2^*t*^|
|5|unauthorized read|attack the encryption of the plaintext with *K1*|anyone|any one file|the cipher's security and the secrecy of the encryption key *K1*|2^*k*^| |5|unauthorized read|attack the encryption of the plaintext with *K1*|anyone|any one file|the cipher's security and the secrecy of the encryption key *K1*|2^*k*^|
|6|unauthorized read|figure out the input to the hash function that generates *S*|anyone|any one file|the hash function's pre-image resistance on *S*|brute force on *R* is !#2| |6|unauthorized read|figure out the input to the hash function that generates *S*|anyone|any one file|the hash function's pre-image resistance on *S*|brute force on *R* is !#2|
|7|unauthorized deletion|brute force KD|anyone|any one file|secrecy of *KD*| |7|unauthorized deletion|brute force KD|anyone|any one file|secrecy of *KD*|2^*d*^|
|8|unauthorized deletion|figure out the destroy key KD from Dhash|anyone|any one file|the hash function's pre-image resistance on *Dhash*| |8|unauthorized deletion|figure out the destroy key KD from Dhash|anyone|any one file|the hash function's pre-image resistance on *Dhash*|brute force on *KD* is !#7|
|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| |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|
|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*^|
|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*^|
where *k* = bitlength(*K1*), *n* = bitlength(*R*), *t* = bitlength(*T*), *d* = bitlength(*KD*). where *k* = bitlength(*K1*), *n* = bitlength(*R*), *t* = bitlength(*T*), *u* = bitlength(*U*), *d* = bitlength(*KD*).
1. *shape-shifter immutable file*: creator creates more than one file matching the immutable file readcap 1. *shape-shifter immutable file*: creator creates more than one file matching the immutable file readcap
2. *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 2. *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