EXERCISE 3 — Which guarantee is violated?
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(a) An ISP injects an ad banner into a web page.
    VIOLATED: Integrity
    Why: the page content was MODIFIED in transit between the server and
    you. The data you received is no longer what the server sent. Tamper-
    detection (integrity) is exactly what catches this — over HTTPS the
    altered bytes would fail the record's integrity check and the
    connection would error out rather than render the injected ad.

(b) Someone on your Wi-Fi reads your session cookie.
    VIOLATED: Confidentiality
    Why: this is passive READING of data on the wire — eavesdropping. The
    attacker didn't change anything or impersonate anyone; they simply saw
    plaintext they shouldn't. Encryption (confidentiality) makes the
    captured bytes meaningless scramble.

(c) You connect to a rogue access point posing as your bank's site.
    VIOLATED: Authentication
    Why: the attacker is PRETENDING TO BE the server (impersonation). Even
    if that fake connection were encrypted, you'd be privately talking to
    the wrong party. Certificate-based authentication is what stops this:
    the rogue server can't present a valid certificate for the bank's
    domain that chains to a trusted CA, so the browser refuses / warns.

SUMMARY OF THE MAPPING:
  eavesdropping (read)        -> breaks CONFIDENTIALITY -> fixed by encryption
  tampering (modify)          -> breaks INTEGRITY       -> fixed by MAC/AEAD checks
  impersonation (pretend)     -> breaks AUTHENTICATION  -> fixed by certificates

  A man-in-the-middle can attempt all three at once; TLS is designed so
  that defeating authentication (c) also shuts down a MITM's ability to
  do (a) and (b) undetected.