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PKC
2005
Springer

From Fixed-Length to Arbitrary-Length RSA Encoding Schemes Revisited

13 years 9 months ago
From Fixed-Length to Arbitrary-Length RSA Encoding Schemes Revisited
To sign with RSA, one usually encodes the message m as µ(m) and then raises the result to the private exponent modulo N. In Asiacrypt 2000, Coron et al. showed how to build a secure RSA encoding scheme µ′ (m) for signing arbitrarily long messages from a secure encoding scheme µ(m) capable of handling only fixed-size messages, without making any additional assumptions. However, their construction required that the input size of µ be larger than the modulus size. In this paper we present a construction for which the input size of µ does not have to be larger than N. Our construction shows that the difficulty in building a secure encoding for RSA signatures is not in handling messages of arbitrary length, but rather in finding a secure encoding function for short messages, which remains an open problem in the standard model.
Julien Cathalo, Jean-Sébastien Coron, David
Added 28 Jun 2010
Updated 28 Jun 2010
Type Conference
Year 2005
Where PKC
Authors Julien Cathalo, Jean-Sébastien Coron, David Naccache
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