Girraj Kumar Verma

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In 2012, Singh and Verma proposed an ID-based proxy signature scheme with message recovery. In this paper, we show that their scheme is vulnerable to the forgery attack, and an adversary can forge a valid proxy signature for any message with knowing a previous valid proxy signature. In addition, there is a security flaw in their proof. Furthermore, we(More)
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(More)
A blind signature scheme is a cryptographic protocol for obtaining a signature from a signer such that the signer’s view of the protocol cannot be linked to the resulting message signature pair. In this paper we have proposed two blind signature schemes using braid groups. The security of given schemes depends upon conjugacy search problem in Braid groups.
Proxy signatures, introduced by Mambo, Usuda and Okamoto, allow a designated person to sign on behalf of an original signer. Braid groups has been playing an important role in the theory of cryptography as these are non commutative groups used in cryptography. Some digital signature schemes have been given but no proxy signature has been introduced over(More)
A blind signature scheme is a cryptographic primitive in which a user can obtain a signature from the signer without revealing any information about message signature pair. Blind signatures are used in electronic payment systems, electronic voting machines etc. The anonymity of blind signature scheme can be misused by criminals by money laundering or by(More)
In this paper, we reinvestigate the security analysis of blind signature scheme over braid groups proposed by Verma in 2008. A blind signature scheme is a cryptographic primitive used for e-commerce for getting a signature from the signer without revealing any information about its contents. These schemes are especially used in e-transactions, e-votings,(More)
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