Hashes, Signatures and Certificates · seed 1 · A4, ink-friendly. The answer key prints on its own page for grown-ups.
En anglais

Fingerprints, seals, and chains of trust

Computing · Networks & Security · ages 21-22
Name ______________________   Date ____________

  1. What does a signature made with a private key prove?

    • That the statement is certainly true
    • Who produced the statement
    • That the site is safe

  2. What is a hash?

    • A short fingerprint of some data
    • A long backup of a whole server
    • A type of password manager program

  3. Two different files can easily be crafted to share one fingerprint.

    Circle one:   True   False

  4. What claim does a certificate sign?

    • That a key belongs to a name
    • That a site has good design quality
    • That traffic is free

  5. Your recomputed fingerprint differs from the posted one. What do you know?

    • The file is definitely virus free forever
    • The file changed after the fingerprint
    • The author changed their name recently

  6. What does the browser check at each chain link?

    • Page colors and fonts on display
    • Signatures, names, and dates
    • The owner birthday on record

  7. A signed statement says the moon is cheese. What does the signature settle?

    • That cheese science is certainly correct
    • Who signed it, not if it is true
    • That the moon changed shape

  8. The chain verifies up to a root on your computer. Who do you end up trusting?

    • The website alone with no help at all
    • Your own typing speed on the keys
    • The root keeper vouching down
LightMySky · lightmysky.comW1-mt_qLHm767U87-s1

Answer key

For grown-ups. Fold this page away before handing over the rest.

Fingerprints, seals, and chains of trust W1-mt_qLHm767U87-s1

  1. Who produced the statement · Only the key holder could have signed it, checked with the public key, which names the author.
  2. A short fingerprint of some data · A hash compresses data into a short fingerprint that changes with any edit.
  3. False · Crafting a match is impractical, which is why tampering shows.
  4. That a key belongs to a name · The signed statement binds a public key to a name like example dot com.
  5. The file changed after the fingerprint · A mismatch means something altered the data after the fingerprint.
  6. Signatures, names, and dates · Each link must verify, name the right site, and still be valid.
  7. Who signed it, not if it is true · Signatures prove authorship while saying nothing about truth.
  8. The root keeper vouching down · Trust flows down the signatures from a root you already hold.
Worksheet · LightMySky