An identity authentication method, implemented by a wearable device comprising a payment protocol interface configured to communicate with a service application of a payment type, the service application requiring an identity authentication operation to the wearable device during specific service execution, the method specifically comprising: configuring the wearable device to include the payment protocol interface for the communication between the wearable device and the service application of the payment type, wherein the payment protocol interface is dedicated to the payment type of the service application, wherein the payment protocol interface is configured to identify a unique payment type identifier corresponding to the service application of the payment type in a message from identity authentication request messages received from different service applications including the service application and to proceed with identity authentication with the message; receiving, by the wearable device via the payment protocol interface, an identity authentication request message sent by a server corresponding to the service application of the payment type, wherein the identity authentication request message is sent by the server to the wearable device after the server receives a service request of the service application of the payment type, and wherein the payment protocol interface processes the identity authentication request message only if the identity authentication request includes the unique identifier of the service application of the payment type; verifying, by the wearable device, a signature in the identity authentication request message according to a public key of the service application of the payment type; acquiring, by the wearable device if the verification succeeds, service authentication information of an account corresponding to the identity authentication request message from locally pre-stored service authentication information; and returning, by the wearable device, a verification response message that comprises the acquired service authentication information to the server via the payment protocol interface. configuring the wearable device to include the payment protocol interface for the communication between the wearable device and the service application of the payment type, wherein the payment protocol interface is dedicated to the payment type of the service application, wherein the payment protocol interface is configured to identify a unique payment type identifier corresponding to the service application of the payment type in a message from identity authentication request messages received from different service applications including the service application and to proceed with identity authentication with the message; receiving, by the wearable device via the payment protocol interface, an identity authentication request message sent by a server corresponding to the service application of the payment type, wherein the identity authentication request message is sent by the server to the wearable device after the server receives a service request of the service application of the payment type, and wherein the payment protocol interface processes the identity authentication request message only if the identity authentication request includes the unique identifier of the service application of the payment type; verifying, by the wearable device, a signature in the identity authentication request message according to a public key of the service application of the payment type; acquiring, by the wearable device if the verification succeeds, service authentication information of an account corresponding to the identity authentication request message from locally pre-stored service authentication information; and returning, by the wearable device, a verification response message that comprises the acquired service authentication information to the server via the payment protocol interface.