A non-repudiation system for facilitating secure delivery of digital content to a remote user over a network, the system comprising: a content server (74, 98) adapted to receive a request for digital content from the user and adapted to deliver digital content requested by the user to a remote device over the network; an input device (72, 92) adapted to receive user authentication data uniquely identifying the user; and an authentication server (78, 94) adapted to receive the user authentication data from the input device for verifying the user's identity and determining whether the user is authorized to receive the requested digital content, upon verifying the user's identity and determining that the user is authorized to receive the requested digital content, the authentication server adapted to send an authorization message to the content server to instruct the content server to deliver the requested content to the remote device, wherein the content server is adapted to send an authentication request to the authentication server in response to receiving the request for digital content from the user, and the authentication server is adapted to send an input request to the input device in response to receiving the authentication request from the content server, the input request prompting the user to input the user authentication data; characterised in that the authorization message does not disclose the identity of the user requesting the content such that the authentication server is configured to shield the user's identity from the content server, and the authentication request does not identify the content requested by the user such that the content server is adapted to shield the requested digital content from the authentication server (78, 94). a content server (74, 98) adapted to receive a request for digital content from the user and adapted to deliver digital content requested by the user to a remote device over the network; an input device (72, 92) adapted to receive user authentication data uniquely identifying the user; and an authentication server (78, 94) adapted to receive the user authentication data from the input device for verifying the user's identity and determining whether the user is authorized to receive the requested digital content, upon verifying the user's identity and determining that the user is authorized to receive the requested digital content, the authentication server adapted to send an authorization message to the content server to instruct the content server to deliver the requested content to the remote device, wherein the content server is adapted to send an authentication request to the authentication server in response to receiving the request for digital content from the user, and the authentication server is adapted to send an input request to the input device in response to receiving the authentication request from the content server, the input request prompting the user to input the user authentication data; characterised in that the authorization message does not disclose the identity of the user requesting the content such that the authentication server is configured to shield the user's identity from the content server, and the authentication request does not identify the content requested by the user such that the content server is adapted to shield the requested digital content from the authentication server (78, 94).