torrent.go | 5 +++--

diff --git a/torrent.go b/torrent.go
index 147c3a98b1e6585a32b623b0b1390ce06989a82e..eefee14c2f0b10335567d9076fdd4c70422566f1 100644
--- a/torrent.go
+++ b/torrent.go
@@ -2,6 +2,7 @@ package torrent
 
 import (
 	"container/heap"
+	"crypto/sha1"
 	"errors"
 	"fmt"
 	"io"
@@ -202,8 +203,8 @@ 	return len(t.metadataBytes)
 }
 
 func infoPieceHashes(info *metainfo.Info) (ret []string) {
-	for i := 0; i < len(info.Pieces); i += 20 {
-		ret = append(ret, string(info.Pieces[i:i+20]))
+	for i := 0; i < len(info.Pieces); i += sha1.Size {
+		ret = append(ret, string(info.Pieces[i:i+sha1.Size]))
 	}
 	return
 }