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Hwang modified version of Neumann Stubblebine

Author(s): T. Hwang and N.Y. Lee and C.M. Li and M.Y. Ko and Y.H. Chen  (1995)

Summary: Modified version of the Neumann Stubblebine protocol, to correct attack of the repeated authentification part.

Protocol specification (in common syntax)

A, B, S :   principal
Na, Ma, Nb, Mb :   number
Kas, Kbs, Kab :   key
Ta, Tb :   time

1.   A -> B :   A, Na
2.   B -> S :   B, {A, Na, Tb, Nb}Kbs
3.   S -> A :   {B, Na, Kab, Tb}Kas, {A, Kab, Tb}Kbs, Nb
4.   A -> B :   {A, Kab, Tb}Kbs, {Nb}Kab
5.   A -> B :   Ma, {A, Kab, Tb}Kbs
6.   B -> A :   Mb, {Mb}Kab
7.   A -> B :   {Mb}Kab

Description of the protocol rules

See Neumann Stubblebine. The messages 1-4 are the part concerning the generation and exchange of the session key Kab. The messages 5-7 is the repeated authentication part.


See Neumann Stubblebine.



Claimed attacks

In [CJ95], Clark and Jacob describe an attack depending on the encryption method (when cipher block chaining is performed for encryption).

See also

Neumann Stubblebine


John A Clark and Jeremy L Jacob. On the security of recent protocols. Information processing Letters, 56:151--155, 1995.

Tzonelih Hwang, Narn-Yoh Lee, Chuang-Ming Li, Ming-Yung Ko, and Yung-Hsiang Chen. Two attacks on neumann-stubblebine authentication protocols. Information Processing Letters, 53:103 -- 107, 1995.
last modified 11/11/2002.
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