From b873c223aef129ee907eee4e9c86e1fc8342eeda Mon Sep 17 00:00:00 2001
From: davidsarah <>
Date: Sun, 11 Oct 2009 02:07:43 +0000
Subject: [PATCH] cost of #8

[Imported from Trac: page NewCaps/WhatCouldGoWrong, version 13]
---
 NewCaps/WhatCouldGoWrong.md | 6 +++---
 1 file changed, 3 insertions(+), 3 deletions(-)

diff --git a/NewCaps/WhatCouldGoWrong.md b/NewCaps/WhatCouldGoWrong.md
index b7d4e2b..1137d70 100644
--- a/NewCaps/WhatCouldGoWrong.md
+++ b/NewCaps/WhatCouldGoWrong.md
@@ -5,19 +5,19 @@ This is about What Could Go Wrong with the "Elk Point 2" immutable file caps: <h
 |#|*what bad thing could happen*|*how*|*who could do it*|*what could they target*|*what crypto property prevents it*|*how expensive to brute force* [5]footnote|
 |1|shape-shifter immutable file [1]footnote|collide read-cap (*R*,*T*)|creator of a file|their own file|the hash function's and cap format's collision resistance on the read-cap (*R*,*T*). This also depends on the encryption of *K1* being deterministic and correct.|2^(*n*+*t*)/2^|
 |2|unauthorized read|attack the encryption of *K1* with *R*|anyone|any one file|the cipher's security and the secrecy of the read-key *R*|2^*n*^|
-|3|forgery of immutable file|generate a matching read-cap (*R*,*T*) for someone else's file|anyone|any one file|the hash function's and cap format's second-pre-image resistance on (*R*,*T*)|2^*n*+*t*^|
+|3|forgery of immutable file|generate a matching read-cap (*R*,*T*) for someone else's file|anyone|any one file|the hash function's and cap format's second-pre-image resistance on (*R*,*T*). This also depends on the encryption of *K1* being deterministic and correct.|2^*n*+*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*^|
 |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*|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*|brute force on *KD* is !#7|
+|8|unauthorized deletion|figure out the destroy key KD from Dhash|anyone|any one file|the hash function's pre-image resistance on *Dhash*|2^min(*d*,*dh*)^|
 |9|denial of service|prevent access to servers holding sufficient shares (by controlling some of them, or by attacking them or the network)|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 [3]footnote|restore a deleted file's shares by controlling the relevant servers|anyone|any one file|not prevented by crypto|n/a|
 |12|undeletion [3]footnote|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*^|
 |13|accidental collision|storage indices (*S1*,*T1*) and (*S2*,*T2*) collide accidentally|n/a|any two files|approximately random distribution of hash function outputs|[4]footnote|
 
-where *k* = bitlength(*K1*), *n* = bitlength(*R*), *t* = bitlength(*T*), *u* = bitlength(*U*), *d* = bitlength(*KD*).
+where *k* = bitlength(*K1*), *n* = bitlength(*R*), *t* = bitlength(*T*), *u* = bitlength(*U*), *d* = bitlength(*KD*), *dh* = bitlength(*Dhash*).
 
 1. *shape-shifter immutable file*: creator creates more than one file matching the immutable file readcap