When a first device receives an indication to establish a communication with a second device, a feature character string is generated. The first device is associated with a first public key and a first private key. The second device is associated with a second public key and a second private key. The second public key of the second device is obtained. The second public key is used to encrypt the feature character string. A first identification of the first device is at least partly based on the encrypted feature character string and is published. When the feature character string is obtained after decryption, the first public key of the first device is obtained. The second identification is an identification encrypted by the first public key. In response to a determination that the feature character string is obtained after decryption of the second identification, the communication between the first device and the second device is established.