From 19f88c266b5ad8787f69857585e22d724f8bc151 Mon Sep 17 00:00:00 2001
From: davidsarah <>
Date: Sun, 11 Oct 2009 00:50:00 +0000
Subject: [PATCH] r -> n (r would have been more consistent, but n is what the
 diagram uses)

[Imported from Trac: page NewCaps/WhatCouldGoWrong, version 5]
---
 NewCaps/WhatCouldGoWrong.md | 8 +++++---
 1 file changed, 5 insertions(+), 3 deletions(-)

diff --git a/NewCaps/WhatCouldGoWrong.md b/NewCaps/WhatCouldGoWrong.md
index 40c56f8..050b11e 100644
--- a/NewCaps/WhatCouldGoWrong.md
+++ b/NewCaps/WhatCouldGoWrong.md
@@ -3,13 +3,15 @@ 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*|
-|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^(*r*+*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^*r*^|
-|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^*r*+*t*^|
+|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*^|
 |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 attack on *R* is !#2|
 
+where *k* = bitlength(*K1*), *n* = bitlength(*R*), *t* = bitlength(*T*).
+
 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