Patent ID: 8332628

Claim:
A secured data access method for a low-performance electronic tag, comprising the steps of: in a process of writing data, encrypting and writing by a first reader-writer a message, MSG, into the electronic tag; in a process of reading the data, transmitting by a second reader-writer a data request packet to the electronic tag, the data request packet is adapted to trigger the electronic tag to transmit a data response packet to the second reader-writer; transmitting by the electronic tag to the second reader-writer the data response packet comprising an ID 1 field, a TTP field, a PKeyID field, a CP field, a CMSG field and an MIC field, wherein the ID 1 field is the identity of the first reader-writer writing the data, the TTP field is the identity of a trusted third party, the PKeyID field is a key identifier selected and written by the first reader-writer into the electronic tag, the CP field is a CP value equal to r·P calculated and written by the first reader-writer into the electronic tag with r being a secret random number selected by the first reader-writer and P being a generation element of G 1 in a q-order cyclic group, the CMSG field is a cipher text of the MSG written by the first reader-writer into the electronic tag, and the MIC field is an integrity check value, MIC, equal to h(ID 1 ∥S 1 ∥PKeyID∥CMSG∥CP) calculated and written by the first reader-writer into the electronic tag with S 1 being a private key of the first reader-writer and h(x) being a unidirectional hash function; transmitting by the second reader-writer to the trusted third party a key request packet comprising an ID 2 field, the TTP field, a Nonce field, the ID 1 field, the PKeyID field, the CP field, the CMSG field, the MIC field and an MIC 1 field, wherein the ID 2 field is the identity of the second reader-writer reading the data, the Nonce field is a one-time random number selected by the second reader-writer, and the MIC 1 field is a message integrity check value, MIC 1 , calculated by the second reader-writer as h(ID 2 ∥S 2 ∥TTP∥Nonce∥MIC) with S 2 being a private key of the second reader-writer; verifying by the trusted third party the identities of the second reader-writer and the first reader-writer for validity respectively in response to the key request packet, and after the verification is passed, transmitting to the second reader-writer a key response packet comprising the ID 2 field, the TTP field, a CSkeyID field, a CP 1 field, the Nonce field and an MIC 2 field, wherein the CP 1 field is a CP 1 value equal to r 1 ·P calculated and transmitted by the trusted third party to the second reader-writer with r 1 being a secret random number selected by the trusted third party; and deriving by the second reader-writer a plain text of the MSG of the electronic tag from the key response packet.