diff --git a/programs/pkey/rsa_sign.c b/programs/pkey/rsa_sign.c
index d9ba3bb..ebc88e4 100644
--- a/programs/pkey/rsa_sign.c
+++ b/programs/pkey/rsa_sign.c
@@ -147,7 +147,7 @@
     }
 
     if( ( ret = mbedtls_rsa_pkcs1_sign( &rsa, NULL, NULL, MBEDTLS_MD_SHA256,
-                                20, hash, buf ) ) != 0 )
+                                32, hash, buf ) ) != 0 )
     {
         mbedtls_printf( " failed\n  ! mbedtls_rsa_pkcs1_sign returned -0x%0x\n\n", (unsigned int) -ret );
         goto exit;