diff --git a/dsa-verify.c b/dsa-verify.c
index ba73d344400f442384dc95eaf77d8f57224cefa5..43d76c77c0db5fb8810aa2b43fde44605e9d986d 100644
--- a/dsa-verify.c
+++ b/dsa-verify.c
@@ -34,7 +34,7 @@
 #include <stdlib.h>
 
 int
-dsa_verify(struct dsa_public_key *key,
+dsa_verify(const struct dsa_public_key *key,
 	   struct sha1_ctx *hash,
 	   const struct dsa_signature *signature)
 {