A method comprising: a) receiving (step 3, 208, 304), at a directory server (27, 48, 56, 76), an alias identifier, wherein the alias identifier is associated with an account identifier for an account of a presenter; b) determining, by the directory server (27, 48, 56, 76), an access control server associated with the trusted party using the alias identifier; c) sending (step 3, 305), by the directory server (27, 48, 56, 76), a verification request message (VE Req(m)) to the access control server associated with the trusted party after receiving (step 3, 208, 304) the verification request message (VE Req(m)) from a merchant plug-in (28, 74) and after determining the associated trusted party, where the verification request message (VE Req(m)) requests information regarding whether the trusted party or the presenter participates in an authentication program; d) receiving (step 4, 306), at the directory server (27, 48, 56, 76), a verification response message (VE Res(m)), from the access control server wherein the verification response message (VE Res(m)) indicates whether the trusted party or the presenter participates in the authentication program to indicate an authentication availability of the presenter, and e) sending (step 4, 210, 307), by the directory server (27, 48, 56, 76), the verification response message (VE Res(m)) to the merchant plug-in (28, 74); wherein, in case the trusted party and the presenter participate in the authentication program, the method further comprises: f) receiving (step 5), by the directory server (27, 48, 56, 76), a payer authentication request message (PA Req(m)) from the merchant plug-in (28, 74); and g) transmitting (step 5), by the directory server (27, 48, 56, 76), the payer authentication request message (PA Req(m)) to the access control server (25, 80), wherein the access control server (25, 80) subsequently sends (step 6, 402), using the directory server (27, 48, 56, 76), an authentication request message to the presenter and receives (step 8, 405), using the directory server (27, 48, 56, 76), an authentication response message from the presenter, h) sending (step 9, 407), by the access control server (26, 80), a payer authentication response message (PA Res(m)) to the merchant plug-in (28, 74), wherein the merchant plug-in (28, 74) initiates an authorization process with an authorization system. a) receiving (step 3, 208, 304), at a directory server (27, 48, 56, 76), an alias identifier, wherein the alias identifier is associated with an account identifier for an account of a presenter; b) determining, by the directory server (27, 48, 56, 76), an access control server associated with the trusted party using the alias identifier; c) sending (step 3, 305), by the directory server (27, 48, 56, 76), a verification request message (VE Req(m)) to the access control server associated with the trusted party after receiving (step 3, 208, 304) the verification request message (VE Req(m)) from a merchant plug-in (28, 74) and after determining the associated trusted party, where the verification request message (VE Req(m)) requests information regarding whether the trusted party or the presenter participates in an authentication program; d) receiving (step 4, 306), at the directory server (27, 48, 56, 76), a verification response message (VE Res(m)), from the access control server wherein the verification response message (VE Res(m)) indicates whether the trusted party or the presenter participates in the authentication program to indicate an authentication availability of the presenter, and e) sending (step 4, 210, 307), by the directory server (27, 48, 56, 76), the verification response message (VE Res(m)) to the merchant plug-in (28, 74); f) receiving (step 5), by the directory server (27, 48, 56, 76), a payer authentication request message (PA Req(m)) from the merchant plug-in (28, 74); and g) transmitting (step 5), by the directory server (27, 48, 56, 76), the payer authentication request message (PA Req(m)) to the access control server (25, 80), wherein the access control server (25, 80) subsequently sends (step 6, 402), using the directory server (27, 48, 56, 76), an authentication request message to the presenter and receives (step 8, 405), using the directory server (27, 48, 56, 76), an authentication response message from the presenter, h) sending (step 9, 407), by the access control server (26, 80), a payer authentication response message (PA Res(m)) to the merchant plug-in (28, 74),