title: Revision of J3Gen and Validity of the Attacks by Peinado et al.
abstract: This letter is the reply to: Remarks on Peinado et al.'s Analysis of J3Gen by J. Garcia-Alfaro, J. Herrera-Joancomartí and J. Melià-Seguí published in Sensors 2015, 15, 6217-6220. Peinado et al. cryptanalyzed the pseudorandom number generator proposed by Melià-Seguí et al., describing two possible attacks. Later, Garcia-Alfaro claimed that one of this attack did not hold in practice because the assumptions made by Peinado et al. were not correct. This letter reviews those remarks, showing that J3Gen is anyway flawed and that, without further information, the interpretation made by Peinado et al. seems to be correct.
authors.affiliation: Escuela Técnica Superior de Ingeniería de Telecomunicación, Universidad de Málaga, Málaga 29071, Spain. apeinado@ic.uma.es.
authors.forename: Alberto
authors.initials: A
authors.lastname: Peinado
authors.affiliation: Escuela Técnica Superior de Ingeniería de Telecomunicación, Universidad de Málaga, Málaga 29071, Spain. munilla@ic.uma.es.
authors.forename: Jorge
authors.initials: J
authors.lastname: Munilla
authors.affiliation: Instituto de Tecnologías Físicas y de la Información, Consejo Superior de Investigaciones Científicas, Madrid 28006, Spain. amparo@iec.csic.es.
authors.forename: Amparo
authors.initials: A
authors.lastname: Fúster-Sabater
keywords: EPCglobal Gen2; Radio Frequency Identification; cryptanalytic attack; pseudo random number generators; security