delete trailing whitespace in xxx-what-uses-sha1.txt

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.