Linkability of Blind Signature Schemes over Braid Groups

Blindness and unforgeability are two essential security requirements of a secure blind signature scheme. Blindness means that after interacting with various users, the signer can never be able to link a valid message pair. Blindness is meaningless if after interacting with various users, the signer is able to link a valid message signature pair. This security vulnerability is known as linkability attack. Recently, Verma proposed two blind signature schemes over braid groups. Verma claimed that the proposed schemes are secure against all possible security vulnerabilities and also satisfy all essential securities properties.This paper reviews Verma’s proposed blind signature schemes and found that these scheme do not withstand against the linkability vulnerability

A Strong Blind Signature Scheme over Braid Groups

The rapid development of quantum computing makes public key cryptosystems not based on commutative algebraic systems hot topic. Because of the non-commutativity property, the braid group with braid index more than two becomes a new candidate for constructing cryptographic protocols. A strong blind signature scheme is proposed based on the difficulty of the one-more matching conjugacy problem in the braid groups, in which the signer can not relate the signature of the blinded message to that of the original message. The usage of random factor ensures that the blind signatures of the same message are different and avoids the weakness of simultaneous conjugating. The scheme can resist the adaptively chosen-message attack under the random oracle model

On the Security of a Proxy Blind Signature Scheme over Braid Groups

A proxy blind signature scheme is the combination of proxy signature and blind signature scheme. In 2009,Verma proposed a proxy blind signature scheme over braid groups. Verma claimed that the proposed scheme is secure against all possible security lapses and also satisfy all essential security attributes.This paper analyzes Verma’s proposed scheme and found that this scheme suffers with the serious security vulnerabilities. This paper show that the proposed scheme does not satisfy unforgeability and unlinkability, which are two essential security requirement of a secure proxy blind signature scheme

A Note on the Linkability of Blind Signature Schemes over Braid Groups

Blindness and unforgeability are two essential security requirements of a secure blind signature scheme. Blindness means that after interacting with various users, the signer can never be able to link a valid message pair. Blindness is meaningless if after interacting with various users, the signer is able to link a valid message signature pair. This security vulnerability is known as linkability attack. Recently, Verma proposed two blind signature schemes over braid groups. Verma claimed that the proposed schemes are secure against all possible security vulnerabilities and also satisfy all essential securities properties. This paper reviews Verma’s proposed blind signature schemes and found that these scheme do not withstand against the linkability vulnerability