Subliminal channels in the identity-based threshold ring signature

Abstract

Subliminal signature schemes enable senders to hide subliminal messages in a digital signature such that no one besides the authorised subliminal message receiver (called designated receiver) can extract subliminal messages from that signature. This paper is the first to construct subliminal channels on the identity-based threshold ring signature scheme. Two types of subliminal channels are proposed. The first is the unknown-sender subliminal channel, wherein the sender is anonymously sending the subliminal message through an identity-based threshold ring signature. Although the designated receiver can extract the subliminal message and confirm that it is from the known ring of signers, he/she cannot identify the real sender. The other proposed subliminal channel is the known-sender subliminal channel in which the designated receiver can identify the actual sender. Furthermore, the proposed unknown-sender subliminal channel can be extended to permit the sender to send multiple subliminal messages to multiple designated receivers via a single threshold ring signature.

Keywords:

• digital signature
• subliminal channel
• ID-based signature
• threshold ring signature; bilinear pairing

2000 AMS Subject Classification :

• 94A60

Acknowledgements

The authors would like to thank the editors and the anonymous reviewers for their very helpful and valuable comments to enhance the clarity of the manuscript. This research is supported by the National Science Council, Taiwan, Republic of China under the Contract No. NSC 95-2221-E-006-071.