Secure communication between mobile terminals using private public key pairs stored on contactless smartcards

摘要

Secure communication uses smart cards (130, 230) each holding respective pairs of encryption and decryption keys, encrypted by a predetermined key (MSK). A first mobile station (100) receives from a smart card (130) by wireless means, an encrypted pair of encryption and decryption keys and recovers therefrom a first encryption key (SCE1) and a first decryption key (SCD1) using the first station's own copy of the predermined key (MSK). The first station (100) transfers to a second mobile station (200) the first encryption key (SCE1), receives through the system from the second station (200) information encrypted with the first encryption key (SCE1) and decrypts it with the first decryption key (SCD1) to produce encrypted communication from the second station (200) to the first station (100). The station stores the encryption/decryption keys for only the duration of each call, and the user can easily change stations but still retain privileged access to secure calls as before.