diff --git a/include/polarssl/config.h b/include/polarssl/config.h
index 29ba54f..f00a7fc 100644
--- a/include/polarssl/config.h
+++ b/include/polarssl/config.h
@@ -2102,6 +2102,11 @@
 #error "POLARSSL_RSA_C defined, but not all prerequisites"
 #endif
 
+#if defined(POLARSSL_RSASSA_PSS_CERTIFICATES) &&                        \
+    ( !defined(POLARSSL_RSA_C) || !defined(POLARSSL_PKCS1_V21) )
+#error "POLARSSL_RSASSA_PSS_CERTIFICATES defined, but not all prerequisites"
+#endif
+
 #if defined(POLARSSL_SSL_PROTO_SSL3) && ( !defined(POLARSSL_MD5_C) ||     \
     !defined(POLARSSL_SHA1_C) )
 #error "POLARSSL_SSL_PROTO_SSL3 defined, but not all prerequisites"
diff --git a/include/polarssl/x509.h b/include/polarssl/x509.h
index 36f19b0..0ffaca1 100644
--- a/include/polarssl/x509.h
+++ b/include/polarssl/x509.h
@@ -256,9 +256,11 @@
                        x509_buf *alg );
 int x509_get_alg( unsigned char **p, const unsigned char *end,
                   x509_buf *alg, x509_buf *params );
+#if defined(POLARSSL_RSASSA_PSS_CERTIFICATES)
 int x509_get_rsassa_pss_params( const x509_buf *params,
                                 md_type_t *md_alg, md_type_t *mgf_md,
                                 int *salt_len, int *trailer_field );
+#endif
 int x509_get_sig( unsigned char **p, const unsigned char *end, x509_buf *sig );
 int x509_get_sig_alg( const x509_buf *sig_oid, md_type_t *md_alg,
                       pk_type_t *pk_alg );