A method for authentication of a user of a secondary device, operational by the secondary device in an ad hoc personal wireless network comprising a primary device and the secondary device, wherein the primary device and the secondary device are carried by or worn by the user, the method comprising: receiving a primary authentication value representative of a degree of authentication of the user from the primary device via the ad hoc personal wireless network, wherein the primary authentication value indicates a degree of match between a biometric parameter obtained by a biometric parameter detector of the primary device and corresponding features of an authorized user of the primary device; and determining whether to perform a secondary authentication of the user and, if secondary authentication is to be performed, then (a) obtaining at least one biometric parameter representative of the user using the secondary device using a biometric parameter detector of the secondary device, (b) determining a secondary authentication value representative of a degree of authentication of the user based on the at least one biometric parameter obtained using the secondary device, (c) combining the primary authentication value received from the primary device with the secondary authentication value to yield a combined authentication value, and (d) authenticating the user of the secondary device using the combined authentication value by comparing the combined authentication value with a threshold. receiving a primary authentication value representative of a degree of authentication of the user from the primary device via the ad hoc personal wireless network, wherein the primary authentication value indicates a degree of match between a biometric parameter obtained by a biometric parameter detector of the primary device and corresponding features of an authorized user of the primary device; and determining whether to perform a secondary authentication of the user and, if secondary authentication is to be performed, then (a) obtaining at least one biometric parameter representative of the user using the secondary device using a biometric parameter detector of the secondary device, (b) determining a secondary authentication value representative of a degree of authentication of the user based on the at least one biometric parameter obtained using the secondary device, (c) combining the primary authentication value received from the primary device with the secondary authentication value to yield a combined authentication value, and (d) authenticating the user of the secondary device using the combined authentication value by comparing the combined authentication value with a threshold. (a) obtaining at least one biometric parameter representative of the user using the secondary device using a biometric parameter detector of the secondary device, (b) determining a secondary authentication value representative of a degree of authentication of the user based on the at least one biometric parameter obtained using the secondary device, (c) combining the primary authentication value received from the primary device with the secondary authentication value to yield a combined authentication value, and (d) authenticating the user of the secondary device using the combined authentication value by comparing the combined authentication value with a threshold.