diff --git a/programs/pkey/rsa_sign.c b/programs/pkey/rsa_sign.c
index 63ef822..14b87ab 100644
--- a/programs/pkey/rsa_sign.c
+++ b/programs/pkey/rsa_sign.c
@@ -58,7 +58,7 @@
     int ret;
     size_t i;
     rsa_context rsa;
-    unsigned char hash[20];
+    unsigned char hash[32];
     unsigned char buf[POLARSSL_MPI_MAX_SIZE];
     char filename[512];