diff --git a/OneHundredYearCryptography.md b/OneHundredYearCryptography.md
index 81f3d4c..43cbbf6 100644
--- a/OneHundredYearCryptography.md
+++ b/OneHundredYearCryptography.md
@@ -17,7 +17,7 @@ Open questions:
 
 ## Hashing
 
-We'll combine two hash functions using an appropriate combiner depending on the hash function properties that are required, see [Zooko's notes](http://tahoe-lafs.org/pipermail/tahoe-dev/2010-June/004575.html) about hash function combiners. The Comb4P hash function combiner preserves most (but not all) security properties of the hashes is safest combiner in case we actually rely on a hash function property, though because the extra work comes in the form of a set of final Feistel rounds, this may negatively effect performance when combined with the tree hashing mode Tahoe-LAFS uses.
+We'll combine two hash functions using an appropriate combiner depending on the hash function properties that are required, see [Zooko's notes](http://tahoe-lafs.org/pipermail/tahoe-dev/2010-June/004575.html) about hash function combiners. The Comb4P hash function combiner preserves most (but not all) security properties of the hashes, though because the extra work comes in the form of a set of final Feistel rounds, this may negatively effect performance when combined with the tree hashing mode Tahoe-LAFS uses.
 
 ## Signatures