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← Certificate Details - Applied Cryptography

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Showing Revision 2 created 05/25/2016 by Udacity Robot.

  1. Now let's look more closely on what's actually in a certificate,
  2. and we can double click in our browser, depending on the browser.
  3. You're either clicking on the key or clicking on the name, and we can see that
  4. our certificate is telling us we're connected to google.com, and the connection is encrypted.
  5. When we look at more information, we can see more about the certificate,
  6. and we can view the certificate.
  7. Let's look at the details of the certificate, and we can see many things here.
  8. We'll look at several of them. The first is the hierarchy.
  9. We'll talk about that later. That's what give us confidence in the certificate.
  10. Let's look more closely what's in the certificate,
  11. and I've zoomed the window to make it easier to see.
  12. The fields of the certificate are the contents, so you can see it's got a version.
  13. It's got an issuer. Issuer indicates who issued the certificate.
  14. In this case, Thawte, which is now owned by VeriSign.
  15. It's got an expiration time.
  16. It's got the time it was valid from until the time it was valid to.
  17. Then it has the subject, which gives us the name of the owner of the certificate,
  18. which is google.com, and then we can see the public key information.
  19. It says the algorithm of the public key is,
  20. which is using RSA Encryption, and we talked about PKCS in unit 4
  21. That's the way of padding to provide security when using RSA,
  22. and we can see the public key.
  23. We can see the modulus is 1024 bits.
  24. That's long enough to be secure with the recommended RSA key sizes today,
  25. and then we can see the exponent, and we see that it's a small exponent.
  26. This is a popular exponent. Many keys use this.
  27. And we talked about, when we look at RSA,
  28. that it's okay that the public key has a small exponent.
  29. What we need is to know that the exponent for the secret key is hard to determine,
  30. so that must be a large number, but the public key can have a small exponent.