Abstract: In a fair blind signature process, a user interacts with a signer in order to complete a 7-tuple (A,e,s,t,xu,x,m) such that Ae=a0a1xa2ma3xua4ta5s (mod n), where a0, a1, a2, a3, a4 and a5 and n are elements of the Signer's public key (PUBKs). During the signature-issuing phase the user (U) provides the signer (S) with a data element (a1x) encrypted according to a key (f) known to a trusted authority (TA), and this data element (a1x) is disclosed during transmission of the signed message. Similarly, the signed message is transmitted associated with second encrypted data comprising a second data element (a3xu) encrypted according to a key (f) known to the trusted authority (TA), and this second data element (a3xu) is disclosed to the Signer during the signature-issuing phase. Thus, the trusted authority (TA) can revoke the anonymity of the digital signature.

Abstract: In an electronic voting process, a voter (Vi) encrypts his vote (vi) according to the encryption scheme (ETM) of a tallier mix-net (50) used to tally up the votes cast. The voter (Vi) obtains on his encrypted vote, (xi), from an admin server module (20), a digital signature according to a fair blind signature scheme (FBSS). The encrypted vote (xi) is encrypted a second time, together with the unblinded digital signature (yi) thereof by the admin server, using the encryption scheme (EM) of a randomizing mix-net (40), to yield an output (ci), and the voter uses his own signature scheme (Si) to sign this, giving (?i). The voter sends an ID code and data including (ci,?i) to a bulletin board server (30). Discrepancies in this vote data can be detected and their origin traced by prompting the randomizing mix-net servers (40) to provide proofs of correctness, and using the signature-tracing mechanism of FBSS.

Abstract: In a fair blind signature process, a user interacts with a signer in order to complete a 7-tuple (A,e,s,t,xu,x,m) such that Ae=a0?1x ?2m ?3u ?4t ?5s (mod n), where a0, a1, a2, a3, a4 and a5 and n are elements of the Signer's public key (PUBKs). During the signature-issuing phase the user (U) provides the signer (S) with a data element (?1x) encrypted according to a key (f) known to a trusted authority (TA), and this data element (?1x) is disclosed during transmission of the signed message. Similarly, the signed message is transmitted associated with second encrypted data comprising a second data element (?3xu) encrypted according to a key (f) known to the trusted authority (TA), and this second data element (?3xu) is disclosed to the Signer during the signature-issuing phase. Thus, the trusted authority (TA) can revoke the anonymity of the digital signature.