Digital signature with a threshold subliminal channel

Simmons first proposed the concept of subliminal channel in 1983. Since then, many subliminal channels based on digital signatures are proposed. A (t,n) threshold scheme allows a secret to be shared among n users so that only t or more users can reconstruct the secret. In this paper, we combine both concepts to propose the first threshold subliminal channel which can convey a subliminal message to a group of users. Deriving the subliminal message relies on the cooperation of t or more users in the group. Moreover, the validation of the subliminal message can be verified in the scheme.