A method for anonymous attestation, comprising: transmitting, by an application on a client device and to a trusted program having access to credentials of a user that authenticate the user to an entity, a first request for an anonymous attestation token attesting to the user's authentication to a second content provider; transmitting, by the trusted program and to an attestation token issuing system, a token request for the anonymous attestation token, the token request including a set of credentials of the user for verification by the attestation token issuing system; and receiving, by the application and from the attestation token issuing system, the anonymous attestation token comprising (i) an attestation token creation timestamp indicating a time of creation of the anonymous attestation token, and (ii) a second digital signature of the attestation token issuing system; receiving, by the application and from a first server hosted on a first domain of a first content provider, an authentication request to authenticate the user to receive content from a second domain of the second content provider different from the first content provider; in response to receiving the authentication request, redeeming, by the application and with the attestation token issuing system, the anonymous attestation token by transmitting, to the attestation token issuing system, the anonymous attestation token with a second request; receiving, by the application and from the attestation token issuing system in response to the second request, a redemption result indicating whether the attestation token was successfully redeemed and is signed by the attestation token issuing system using a digital signature, wherein the redemption result does not include personally identifiable information; and transmitting, by the application and to the first content provider, the redemption result signed by the attestation token issuing system. transmitting, by an application on a client device and to a trusted program having access to credentials of a user that authenticate the user to an entity, a first request for an anonymous attestation token attesting to the user's authentication to a second content provider; transmitting, by the trusted program and to an attestation token issuing system, a token request for the anonymous attestation token, the token request including a set of credentials of the user for verification by the attestation token issuing system; and receiving, by the application and from the attestation token issuing system, the anonymous attestation token comprising (i) an attestation token creation timestamp indicating a time of creation of the anonymous attestation token, and (ii) a second digital signature of the attestation token issuing system; receiving, by the application and from a first server hosted on a first domain of a first content provider, an authentication request to authenticate the user to receive content from a second domain of the second content provider different from the first content provider; in response to receiving the authentication request, redeeming, by the application and with the attestation token issuing system, the anonymous attestation token by transmitting, to the attestation token issuing system, the anonymous attestation token with a second request; receiving, by the application and from the attestation token issuing system in response to the second request, a redemption result indicating whether the attestation token was successfully redeemed and is signed by the attestation token issuing system using a digital signature, wherein the redemption result does not include personally identifiable information; and transmitting, by the application and to the first content provider, the redemption result signed by the attestation token issuing system.