%0 Journal Article
%T High Efficiency of Two Efficient QSDC with Authentication Is at the Cost of Their Security<br>
%A QIN Su-Juan
%A WEN Qiao-Yan
%A MENG Luo-Ming
%A ZHU Fu-Chen
%A <br>
%J 中国物理快报
%D 2009
%I 
%X Two efficient protocols of quantum secure direct communication with authentication Chin. Phys. Lett. 25(2008) 2354] were recently proposed by Liu et al. to improve the efficiency of two protocols presented in Phys. Rev. A 75(2007)026301] by four Pauli operations. We show that the high efficiency of the two protocols is at the expense of their security. The authenticator Trent can reach half the secret by a particular attack strategy in the first protocol. In the second protocol, not only Trent but also an eavesdropper outside can elicit half-information about the secret from the public declaration.
%K 03
%K 67
%K H
%K 03
%K 65
%K Ud<br>
%U http://www.alljournals.cn/get_abstract_url.aspx?pcid=6E709DC38FA1D09A4B578DD0906875B5B44D4D294832BB8E&cid=47EA7CFDDEBB28E0&jid=E27DA92E19FE279A273627875A70D74D&aid=9C32EE340DBCD1C7AB2B33D6B28AC071&yid=DE12191FBD62783C&vid=96C778EE049EE47D&iid=0B39A22176CE99FB&journal_id=0256-307X&journal_name=中国物理快报&referenced_num=0&reference_num=0