Return to Video

Finding Large Primes Solution - Applied Cryptography

  • 0:00 - 0:03
    The answer is, given the assumptions here, P must not be prime.
  • 0:03 - 0:08
    And the reason for that is P is greater than Pn.
  • 0:08 - 0:11
    And we said this set includes all prime numbers--
  • 0:11 - 0:15
    that's the assumption we started with for this proof,
  • 0:15 - 0:17
    and this number's the product of many numbers--
  • 0:17 - 0:19
    all of these are positive, adding 1 to it.
  • 0:19 - 0:22
    So the value of P must be greater that P sub N
  • 0:22 - 0:26
    and that means, according to our assumption about the limited set of all primes,
  • 0:26 - 0:28
    P must not be prime.
  • 0:28 - 0:31
    So since P is not a prime, that means it must be a composite--
  • 0:31 - 0:37
    which means it must be the product of some prime number and some other integer.
  • 0:37 - 0:40
    So that means we can write P as some prime,
  • 0:40 - 0:42
    and we've said all the primes are in this set,
  • 0:42 - 0:44
    so it's something selected from that set,
  • 0:44 - 0:47
    multiplied by some other number--we don't know what Q is
  • 0:47 - 0:49
    other than it must be an integer.
  • 0:49 - 0:54
    So now we have P, which we computed as the product of all these primes plus 1
  • 0:54 - 0:59
    which is equal to some prime from that set times Q.
Title:
Finding Large Primes Solution - Applied Cryptography
Video Language:
English
Team:
Udacity
Project:
CS387 - Applied Cryptography
Duration:
01:00
Udacity Robot edited English subtitles for Finding Large Primes Solution - Applied Cryptography
Gundega added a translation

English subtitles

Revisions Compare revisions