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CATEGORIES:Isaac Newton Institute Seminar Series
SUMMARY:Cryptography and Algorithmic Randomness - Tadaki\,
  K (Chuo University)
DTSTART;TZID=Europe/London:20120706T100000
DTEND;TZID=Europe/London:20120706T103000
UID:TALK38883AThttp://talks.cam.ac.uk
URL:http://talks.cam.ac.uk/talk/index/38883
DESCRIPTION:In modern cryptography\, the random oracle model i
 s widely used as an imaginary framework in which t
 he security of a cryptographic scheme is discussed
 . In the random oracle model\, the cryptographic h
 ash function used in a cryptographic scheme is for
 mulated as a random variable uniformly distributed
  over all possibility of the function\, called the
  random oracle\, and the legitimate users and the 
 adversary against the scheme are modeled so as to 
 get the values of the hash function not by evaluat
 ing it in their own but by querying the random ora
 cle. Since the random oracle is an imaginary objec
 t\, even if the security of a cryptographic scheme
  is proved in the random oracle model\, the random
  oracle has to be instantiated using a concrete cr
 yptographic hash function such as the SHA hash fun
 ctions if we want to use the scheme in the real wo
 rld. However\, it is not clear how much the instan
 tiation can maintain the security originally prove
 d in the random oracle model\, nor is it clear w h
 ether the random oracle can be instantiated someho
 w while keeping the original security. In the pres
 ent talk we investigate this problem using concept
 s and methods of algorithmic randomness. Our resul
 ts use the general form of definitions of security
  notions for cryptographic schemes\, and depend ne
 ither on specific schemes nor on specific security
  notions. \n\n
LOCATION:Seminar Room 1\, Newton Institute
CONTACT:Mustapha Amrani
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