A method for authenticating a first computing device at a second computing device, the method comprising receiving a chain of one or more certificates from the first computing device at the second computing device; characterized by the following steps performed at the second computing device: determining if any of the received one or more certificates contains an identifier corresponding to a certificate contained in a trusted people store, the trusted people store comprising signed certificates of entities deemed by a user of the second computing device to be trustworthy, the signed certificates having been placed in the trusted people store of the second computing device under the direction of the user of the second computing device; authenticating the first computing device if any of the certificates of the trusted people store identifies the first computing device (307, 317), otherwise determining if the last certificate in the chain of the received one or more certificates is signed by a trusted root store entity, wherein the trusted root store entity is identified by a signed certificate placed in a trusted root store of the second computing device, the trusted root store of the second computing device comprising certificates signed by a certificate authority, and wherein further the trusted root store of the second computing device comprises different certificates than the trusted people store of the second computing device; determining if the first certificate in the chain of the one or more certificates identifies the first computing device; determining if each certificate in the chain of the one or more certificates is authenticated by a following certificate in the chain of the one or more certificates (309, 311, 313); and authenticating the first computing device if the last certificate in the chain of the one or more certificates is signed by the trusted root store entity, if the first certificate in the chain of the one or more certificates identifies the first computing device, and if each certificate in the chain of the one or more certificates is authenticated by the following certificate in the chain of the one or more certificates (307, 317). determining if any of the received one or more certificates contains an identifier corresponding to a certificate contained in a trusted people store, the trusted people store comprising signed certificates of entities deemed by a user of the second computing device to be trustworthy, the signed certificates having been placed in the trusted people store of the second computing device under the direction of the user of the second computing device; authenticating the first computing device if any of the certificates of the trusted people store identifies the first computing device (307, 317), otherwise determining if the last certificate in the chain of the received one or more certificates is signed by a trusted root store entity, wherein the trusted root store entity is identified by a signed certificate placed in a trusted root store of the second computing device, the trusted root store of the second computing device comprising certificates signed by a certificate authority, and wherein further the trusted root store of the second computing device comprises different certificates than the trusted people store of the second computing device; determining if the first certificate in the chain of the one or more certificates identifies the first computing device; determining if each certificate in the chain of the one or more certificates is authenticated by a following certificate in the chain of the one or more certificates (309, 311, 313); and authenticating the first computing device if the last certificate in the chain of the one or more certificates is signed by the trusted root store entity, if the first certificate in the chain of the one or more certificates identifies the first computing device, and if each certificate in the chain of the one or more certificates is authenticated by the following certificate in the chain of the one or more certificates (307, 317).