Atsushi Koide

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Undeniable signature is a kind of signatures that the validity or invalidity of a signature can only be verified with the help of the signer. On the other hand, the concept of blind signature is to enable a user to obtain a signature on a message which is unknown to the signer. Following these pioneer works, extended version of these schemes such as(More)
A sanitizing signature scheme, which is a variant of digital signatures, enables a trusted party named sanitizer to modify parts of signed documents without corresponding to the signer. A lot of sanitizing signature schemes have been proposed since 2001. However these schemes are suitable for table-style documents, but none of them are considered for(More)
A restricted universal designated verifier signature scheme proposed by Huang et al., which is a variant of digital signatures, allows a signature holder to convince at most t designated verifiers.The signature will become publicly verifiable when the signature holder uses the signature for t+1 times.The applications of this type of signatures are expected(More)
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