A Note on the Complexity of Breaking Okamoto-Tanaka ID-Based Key Exchange Scheme
Masahiro Mambo, Hiroki Shizuya · 1999
Abstract. The rigorous security of Okamoto-Tanaka identity-based key exchange scheme has been open for a decade. In this paper, we show that (1) breaking the scheme is equivalent to breaking the Diffie-Hellman key exchange scheme over Zn, and (2) impersonation is easier than breaking. The second result is obtained by proving that breaking the RSA publickey cryptosystem reduces to breaking the Diffie-Hellman scheme over Zn with respect to the polynomial-time many-one reducibility. 1