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cs2010 Notes: 23 Security and HTTP

·1 min

Layers #

  • Physical (wire / radio)
  • Data (ethernet / wifi)
  • Network (IP)
  • Transport (TCP)
  • Security (TLS)
  • Application (HTTPS)

TLS #

  • Cryptography
    • Public key
      • Encryption
      • Signatures
    • Secret key
      • Encryption
      • Authentication Codes
  • How do we trust a website?
    • The messages are signed, but by who?
    • The certificate is signed, but by who?
    • Certificate authorities
    • Threat model: Great for buying stuff with a credit card, not good enough for very serious threats.
    • Letsencrypt

HTTP #

Do the simple demo with telnet against homework.quest.

Web App #

$ mkdir edemo; cd edemo
$ pnpm install express

const express = require('express')
const app = express()
const port = 3000

app.get('/', (req, res) => {
  console.log(req);
  res.send('Hello World!')
})

app.listen(port, () => {
  console.log(`Example app listening on port ${port}`)
})

$ node app.js

Then visit localhost:3000 in browser

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