Improvement of Harn's digital signature forDiffie-Hellman public keys
He, Tzong‐Chen Wu · Electronics Letters · 1997
Recently, Harn proposed a digital signature for Diffie-Hellman public keys without using a one-way function (Electron. Lett., 1997, 33, (2), pp.125–126). In the Letter, the authors show that Harn's digital signature is not secure enough to withstand the Nyberg-Rueppel attack. That is, an adversary who discloses one session key can obtain all the other session keys subsequently distributed by the same key exchange protocol. An improvement to Harn's digital signature that can overcome the weakness stated above is also proposed.