1. A knowledge-based authentication method performed by a server for restricting access of a user to a restricted resource, comprising the steps of: challenging said user with one or more questions requiring knowledge by said user, wherein said user previously provided one or more answers to said one or more questions during a set-up phase, wherein at least one of said answers provided by said user encode one or more of historical, inter-relational and contextual information of said user using an encoding scheme defined between said server and said user to signal a fraudulent access attempt; receiving a response from said user to said one or more questions, wherein at least a portion of said response is encoded by said user using said encoding scheme defined between said server and said user to signal said fraudulent access attempt; and granting access to said restricted resource if one or more predefined response criteria are satisfied, wherein said one or more predefined response criteria comprises an assessment of whether said encoded portion of said response satisfies said encoding scheme, wherein at least one of said steps are performed by at least one hardware device.
1. A knowledge-based authentication method performed by a server for restricting access of a user to a restricted resource, comprising the steps of: challenging said user with one or more questions requiring knowledge by said user, wherein said user previously provided one or more answers to said one or more questions during a set-up phase, wherein at least one of said answers provided by said user encode one or more of historical, inter-relational and contextual information of said user using an encoding scheme defined between said server and said user to signal a fraudulent access attempt; receiving a response from said user to said one or more questions, wherein at least a portion of said response is encoded by said user using said encoding scheme defined between said server and said user to signal said fraudulent access attempt; and granting access to said restricted resource if one or more predefined response criteria are satisfied, wherein said one or more predefined response criteria comprises an assessment of whether said encoded portion of said response satisfies said encoding scheme, wherein at least one of said steps are performed by at least one hardware device. 6. The method of claim 1 , wherein said encoding scheme comprises a requirement that said user shall not answer any question that addresses a previously defined blocked topic.