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author | Nick Mathewson <nickm@torproject.org> | 2009-05-02 11:49:45 -0500 |
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committer | Nick Mathewson <nickm@torproject.org> | 2009-05-02 11:49:45 -0500 |
commit | 08e4a077207a5def143cf62ad34ce6c76e6f8300 (patch) | |
tree | 8f1ae921df7489fbf49535734177a4e06a25aacf /doc/spec/proposals | |
parent | 4f9b12e2480d74427e80d6ecd68383b11340ea30 (diff) | |
download | tor-08e4a077207a5def143cf62ad34ce6c76e6f8300.tar.gz tor-08e4a077207a5def143cf62ad34ce6c76e6f8300.zip |
delete trailing whitespace in xxx-what-uses-sha1.txt
Diffstat (limited to 'doc/spec/proposals')
-rw-r--r-- | doc/spec/proposals/ideas/xxx-what-uses-sha1.txt | 36 |
1 files changed, 18 insertions, 18 deletions
diff --git a/doc/spec/proposals/ideas/xxx-what-uses-sha1.txt b/doc/spec/proposals/ideas/xxx-what-uses-sha1.txt index 1e621129be..3112aee1f0 100644 --- a/doc/spec/proposals/ideas/xxx-what-uses-sha1.txt +++ b/doc/spec/proposals/ideas/xxx-what-uses-sha1.txt @@ -15,10 +15,10 @@ Introduction: too long. According to smart crypto people, the SHA-2 functions (SHA-256, etc) - share too much of SHA-1's structure to be very good. RIPEMD-160 is - also based on flawed past hashes. Some people think other hash - functions (e.g. Whirlpool and Tiger) are not as bad; most of these - have not seen enough analysis to be used yet. + share too much of SHA-1's structure to be very good. RIPEMD-160 is + also based on flawed past hashes. Some people think other hash + functions (e.g. Whirlpool and Tiger) are not as bad; most of these + have not seen enough analysis to be used yet. Here is a 2006 paper about hash algorithms. http://www.sane.nl/sane2006/program/final-papers/R10.pdf @@ -91,29 +91,29 @@ What Tor uses hashes for today: A. All signatures are generated on the SHA-1 of their corresponding documents, using PKCS1 padding. - * In dir-spec.txt, section 1.3, it states, - "SIGNATURE" Object contains a signature (using the signing key) - of the PKCS1-padded digest of the entire document, taken from - the beginning of the Initial item, through the newline after + * In dir-spec.txt, section 1.3, it states, + "SIGNATURE" Object contains a signature (using the signing key) + of the PKCS1-padded digest of the entire document, taken from + the beginning of the Initial item, through the newline after the Signature Item's keyword and its arguments." - So our attacker, Malcom, could generate a collision for the hash - that is signed. Thus, a second pre-image attack is possible. + So our attacker, Malcom, could generate a collision for the hash + that is signed. Thus, a second pre-image attack is possible. Vulnerable to regular collision attack only if key is stolen. - If the key is stolen, Malcom could distribute two different + If the key is stolen, Malcom could distribute two different copies of the document which have the same hash. Maybe useful for a partitioning attack? B. Router descriptors identify their corresponding extra-info documents by their SHA-1 digest. - * A third party might use a second pre-image attack to generate a - false extra-info document that has the same hash. The router - itself might use a regular collision attack to generate multiple - extra-info documents with the same hash, which might be useful + * A third party might use a second pre-image attack to generate a + false extra-info document that has the same hash. The router + itself might use a regular collision attack to generate multiple + extra-info documents with the same hash, which might be useful for a partitioning attack. C. Fingerprints in router descriptors are taken using SHA-1. - * The fingerprint must match the public key. Not sure what would - happen if two routers had different public keys but the same + * The fingerprint must match the public key. Not sure what would + happen if two routers had different public keys but the same fingerprint. There could perhaps be unpredictable behaviour. - D. In router descriptors, routers in the same "Family" may be listed + D. In router descriptors, routers in the same "Family" may be listed by server nicknames or hexdigests. * Does not seem critical. E. Fingerprints in authority certs are taken using SHA-1. |