An example operation may include one or more of identifying a query from a requesting entity, where the query requests access to one or more blockchains, converting the query to an expression tree, creating one or more expression tree variations based on the expression tree, the one or more expression tree variations provide one or more different expressions than the expression tree and a same result as the expression tree, determining access conformity between one or more expression tree variations and the expression tree, selecting an expression tree variation with a greatest conformity rating, performing the query using the expression tree variation with the greatest conformity rating, and providing query results to a requesting entity.