diff --git a/hashes/isl-0.21.tar.bz2.sha1 b/hashes/isl-0.21.tar.bz2.sha1
new file mode 100644
index 0000000..a4b001d
--- /dev/null
+++ b/hashes/isl-0.21.tar.bz2.sha1
@@ -0,0 +1 @@
+33e366d59d32330432b5c7f2d0c2fb6664eff224  isl-0.21.tar.bz2