* Shorten SHA-256 hashes used in store path name generation to 160

  bits, then encode them in a radix-32 representation (using digits
  and letters except e, o, u, and t).  This produces store paths like
  /nix/store/4i0zb0z7f88mwghjirkz702a71dcfivn-aterm-2.3.1.  The nice
  thing about this is that the hash part of the file name is still 32
  characters, as before with MD5.

  (Of course, shortening SHA-256 to 160 bits makes it no better than
  SHA-160 in theory, but hopefully it's a bit more resistant to
  attacks; it's certainly a lot slower.)

1 files changed, 6 insertions, 2 deletions

diff --git a/src/libstore/references.cc b/src/libstore/references.cc
index 9b20b980a1b2..5ceae6427617 100644
--- a/src/libstore/references.cc
+++ b/src/libstore/references.cc
@@ -81,8 +81,12 @@ Strings filterReferences(const string & path, const Strings & paths)
     for (Strings::const_iterator i = paths.begin();
          i != paths.end(); i++)
     {
-        string s = string(baseNameOf(*i), 0, 32);
-        parseHash(s);
+        string baseName = baseNameOf(*i);
+        unsigned int pos = baseName.find('-');
+        if (pos == string::npos)
+            throw Error(format("bad reference `%1%'") % *i);
+        string s = string(baseName, 0, pos);
+        // parseHash(htSHA256, s);
         ids.push_back(s);
         backMap[s] = *i;
     }