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Generating ElGamal signatures without knowing the secret key
, 1996
"... . We present a new method to forge ElGamal signatures if the public parameters of the system are not chosen properly. Since the secret key is hereby not found this attack shows that forging ElGamal signatures is sometimes easier than the underlying discrete logarithm problem. 1 Introduction ElGamal ..."
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. We present a new method to forge ElGamal signatures if the public parameters of the system are not chosen properly. Since the secret key is hereby not found this attack shows that forging ElGamal signatures is sometimes easier than the underlying discrete logarithm problem. 1 Introduction ElGamal's digital signature scheme [4] relies on the difficulty of computing discrete logarithms in the multiplicative group IF p and can therefore be broken if the computation of discrete logarithms is feasible. However, the converse has never been proved. In this paper we show that it is sometimes possible to forge signatures without breaking the underlying discrete logarithm problem. This shows that the ElGamal signature scheme and some variants of the scheme must be used very carefully. The paper is organized as follows. Section 2 describes the ElGamal signature scheme. In Section 3 we present a method to forge signatures if some additional information on the generator is known. We show that...
Generalized ElGamal signatures for one message block
, 1994
"... There have been many approaches in the past to generalize the ElGamal signature scheme. In this paper we integrate all these approaches in a generalized ElGamal signature scheme. We also investigate some new types of variations, that haven't been considered before. By this method we obtain numerous ..."
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There have been many approaches in the past to generalize the ElGamal signature scheme. In this paper we integrate all these approaches in a generalized ElGamal signature scheme. We also investigate some new types of variations, that haven't been considered before. By this method we obtain numerous variants of the ElGamal scheme. From these variants, we can extract new, highly efficient signature schemes, which haven't been proposed before. 1. Introduction There have been many approaches to generalize the ElGamal signature scheme [ElGa84, Schn89, AgMV90, NIST91, Schn91, BrMc91, YeLa93, Knob93, NyR293, Har194, NyRu94, HoP194, HoP294, HoP394, Har294]. In this paper we try to integrate all these approaches in a generalized ElGamal signature scheme. We also investigate some new types of variation, that haven't been considered before. By this method we obtain various variants of the ElGamal scheme. The advantage of this proceeding is that we can extract highly efficient schemes out of thes...
MetaElGamal signature schemes using a composite module
, 1994
"... In 1984 ElGamal published the first signature scheme based on the discrete logarithm problem. Since then a lot of work was done to modify and generalize this signature scheme. Very important steps of recent research were the discovery of efficient signature schemes with appendix , e.g. by Schnorr, N ..."
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Cited by 2 (0 self)
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In 1984 ElGamal published the first signature scheme based on the discrete logarithm problem. Since then a lot of work was done to modify and generalize this signature scheme. Very important steps of recent research were the discovery of efficient signature schemes with appendix , e.g. by Schnorr, Nyberg/Rueppel or Harn. All these variants can be embedded into a MetaElGamal signature scheme. Until now all schemes except one have in common that the verification is done over a finite field. In this paper we focus on those schemes where a composite modul n = pq instead of a primemodul p is used in the MetaElGamal signature scheme. An unmodified scheme is cryptoanalysed in this composite mode, further we introduce some new refined modes and give a security and performance analysis of the various schemes. As a result, some schemes can be used in these modes with slight modifications. Although the security of these schemes can't be proven, the advantages are that ffl even existential for...
Generating ElGamal signatures without knowing the secret key
, 1996
"... . We present a new method to forge ElGamal signatures if the public parameters of the system are not chosen properly. Since the secret key is hereby not found this attack shows that forging ElGamal signatures is sometimes easier than the underlying discrete logarithm problem. 1 Introduction El ..."
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. We present a new method to forge ElGamal signatures if the public parameters of the system are not chosen properly. Since the secret key is hereby not found this attack shows that forging ElGamal signatures is sometimes easier than the underlying discrete logarithm problem. 1 Introduction ElGamal's digital signature scheme [4] relies on the difficulty of computing discrete logarithms in the multiplicative group IF p and can therefore be broken if the computation of discrete logarithms is feasible. However, the converse has never been proved. In this paper we show that it is sometimes possible to forge signatures without breaking the underlying discrete logarithm problem. This shows that the ElGamal signature scheme and some variants of the scheme must be used very carefully. The paper is organized as follows. Section 2 describes the ElGamal signature scheme. In Section 3 we present a method to forge signatures if some additional information on the generator is known. We show ...
Implementing Swati Verma’s Digital Signature Schemes based on Integer Factorization and
"... A digital signature is a cryptographic method for verifying the identity of an individual. It can be a process, computer system, or any other entity, in much the same way as a handwritten signature verifies the identity of a person. Digital signatures use the properties of publickey cryptography to ..."
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A digital signature is a cryptographic method for verifying the identity of an individual. It can be a process, computer system, or any other entity, in much the same way as a handwritten signature verifies the identity of a person. Digital signatures use the properties of publickey cryptography to produce pieces of information that verify the origin of the data. Several digital schemes have been proposed as on date based on factorization, discrete logarithm and elliptical curve. However, the Swati Verma and Birendra Kumar Sharma [8] digital signature scheme which combines factorization and discrete logarithm together making it difficult for solving two hard problems from the hackers point of view. This paper presents the implementation of same, with the help of different tools and further analyzes them from different perceptions.
A New Digital Signature Scheme Based on Two Hard Problems
"... Abstract: In this paper, we propose a new signature scheme based on factoring and discrete logarithm. This scheme is based on two hard problems and provides higher level security as compare to a single hard problem. Most of the designated signature schemes are based on a single hard problem. Althoug ..."
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Abstract: In this paper, we propose a new signature scheme based on factoring and discrete logarithm. This scheme is based on two hard problems and provides higher level security as compare to a single hard problem. Most of the designated signature schemes are based on a single hard problem. Although these schemes secure but in a future if an enemy manages to solve this problem, are then he can recover all secret information including secret keys and parameters of the scheme. Our scheme is protected from such four attacks which are most common attacks for signature schemes.