Group-Oriented Convertible Authenticated Encryption Scheme with (t, n) Shared Verification
Han-Yu Lin, Tzong‐Sun Wu, Ting-Yu Huang, Tzu‐Chiang Lin · 2007
Conventional authenticated encryption (AE) schemes put emphasis on the one-to-one setting, which allow one signer to produce an authenticated ciphertext such that only the designated recipient can recover the message and verify its corresponding signature. To meet the need of diversified applications which require simultaneously fulfilling the security requirements of integrity, authenticity, confidentiality and non-repudiation, this paper presents a group-oriented convertible authenticated encryption (CAE) scheme with (t, n) shared verification. Designed mainly for the multi-user setting, the proposed scheme enables one signer to send a confidential message along with the signature to the designated group of n recipients. Any t or more of n designated recipients can cooperatively recover the message and verify its signature while less than or equal to t − 1 can not. Moreover, in case of a later dispute over repudiation, the designated group of recipients has the ability to convert the signature into an ordinary one for convincing anyone of the signer’s dishonesty.