diff --git a/src/encoding/asn1/asn1.go b/src/encoding/asn1/asn1.go
index c90bba47dcf..4408352cff6 100644
--- a/src/encoding/asn1/asn1.go
+++ b/src/encoding/asn1/asn1.go
@@ -162,7 +162,7 @@ type BitString struct {
 }
 
 // At returns the bit at the given index. If the index is out of range it
-// returns false.
+// returns 0.
 func (b BitString) At(i int) int {
 	if i < 0 || i >= b.BitLength {
 		return 0