There is provided an authentication system for validating identity credentials of a user attempting to access a resource provided by a remote resource provision system. The authentication system includes an input configured to receive, from the resource provision system, an authentication request comprising a cryptographic representation of digital identity data of the user and an associated token identifier, where the digital identity data comprises at least one image of an identity credential of the user. The system also includes a processor configured to: determine a pre-stored cryptographic identifier corresponding to the token identifier; and compare the received cryptographic representation with the pre-stored cryptographic identifier. The system further includes an output configured to transmit, to the remote resource provision system and in response to determining a match between the received cryptographic representation and the pre-stored cryptographic identifier, an authentication confirmation indicating successful validation of the digital identity data.