A system of providing a content filtering service, comprising: a network interface adapted to receive from a client terminal via a network a request for retrieving network data from at least one network resource; a store code for storing a code to transmit to said client terminal a client side security script in response to said request; and a processor, connected to said network interface and said store code, and adapted to execute said code for transmitting said client side security script to said client terminal; wherein said client side security script is adapted to be interpreted at said client terminal for authenticating the rendering of at least part of said network data from the at least one network resource; wherein said client side security script is adapted to be executed by a client side processor of said client terminal for authenticating the rendering of at least part of said network data by verifying a compliance of said network data with at least one condition and for presenting said network data based on a detection of said compliance; wherein said code comprises instructions to: extract an identifier of said client from said request, authenticate said identifier, and instruct a routing device of said network to open a data flow for a direct retrieval of said network data from said at least one network resource by said client side security script; and wherein said code comprises instructions to: provide said routing device with a first key; provide said client with a second key; and wherein when said client side security script sends a request for a network resource to said routing device, the request includes said second key, said routing device matches between said first key and said second key for verifying said direct retrieval. a network interface adapted to receive from a client terminal via a network a request for retrieving network data from at least one network resource; a store code for storing a code to transmit to said client terminal a client side security script in response to said request; and a processor, connected to said network interface and said store code, and adapted to execute said code for transmitting said client side security script to said client terminal; wherein said client side security script is adapted to be interpreted at said client terminal for authenticating the rendering of at least part of said network data from the at least one network resource; wherein said client side security script is adapted to be executed by a client side processor of said client terminal for authenticating the rendering of at least part of said network data by verifying a compliance of said network data with at least one condition and for presenting said network data based on a detection of said compliance; wherein said code comprises instructions to: extract an identifier of said client from said request, authenticate said identifier, and instruct a routing device of said network to open a data flow for a direct retrieval of said network data from said at least one network resource by said client side security script; and wherein said code comprises instructions to: provide said routing device with a first key; provide said client with a second key; and wherein when said client side security script sends a request for a network resource to said routing device, the request includes said second key, said routing device matches between said first key and said second key for verifying said direct retrieval. extract an identifier of said client from said request, authenticate said identifier, and instruct a routing device of said network to open a data flow for a direct retrieval of said network data from said at least one network resource by said client side security script; and wherein said code comprises instructions to: provide said routing device with a first key; provide said client with a second key; and wherein when said client side security script sends a request for a network resource to said routing device, the request includes said second key, said routing device matches between said first key and said second key for verifying said direct retrieval. provide said routing device with a first key; provide said client with a second key; and wherein when said client side security script sends a request for a network resource to said routing device, the request includes said second key, said routing device matches between said first key and said second key for verifying said direct retrieval.