diff --git a/src/restic/node.go b/src/restic/node.go
index 253a33e9a..5349b5494 100644
--- a/src/restic/node.go
+++ b/src/restic/node.go
@@ -215,7 +215,7 @@ func (node Node) createFileAt(path string, repo Repository, idx *HardlinkIndex)
 		}
 
 		buf = buf[:cap(buf)]
-		if uint(len(buf)) < size {
+		if len(buf) < CiphertextLength(int(size)) {
 			buf = NewBlobBuffer(int(size))
 		}