diff --git a/library/pk.c b/library/pk.c
index bb55a18..980256a 100644
--- a/library/pk.c
+++ b/library/pk.c
@@ -329,7 +329,8 @@
         return( MBEDTLS_ERR_PK_FEATURE_UNAVAILABLE );
     }
 
-    if( prv->pk_info->type != MBEDTLS_PK_OPAQUE )
+    if( prv->pk_info->type != MBEDTLS_PK_RSA_ALT &&
+        prv->pk_info->type != MBEDTLS_PK_OPAQUE )
     {
         if( pub->pk_info != prv->pk_info )
             return( MBEDTLS_ERR_PK_TYPE_MISMATCH );