Cloud and basic data security

Why this matters

One survey flight can produce tens of gigabytes of images, and you must decide where to process them and what to send to whom. The same data may contain images of people, the locations of sensitive sites or aircraft commands. If it leaks, is altered or is unavailable when needed, the damage can be worse than a failed mission. This module lays the groundwork for both architecture and security; personal-data law is covered in UAT 313 module 5.

What the cloud is

NIST SP 800-145 defines cloud computing as a model in which users reach a shared pool of computing resources over the network on demand, with five essential characteristics:

1. On-demand self-service: add machines or storage yourself without contacting the provider
2. Broad network access
3. Resource pooling: many users share the same resources
4. Rapid elasticity: scale up or down with the workload
5. Measured service: pay for what you actually use

There are four deployment models: private, community, public and hybrid cloud. Organisations with sensitive data often keep originals in a private cloud and send only publishable results to a public cloud.

Edge or cloud

Edge computing means processing close to where data is produced, such as on the drone’s companion computer or a field laptop. NIST SP 500-325 describes the closely related idea of fog computing, which extends cloud services down towards devices. There are three main criteria:

• Response time: tasks that must respond in a fraction of a second, such as obstacle avoidance, must run on the drone
• Bandwidth: large raw data cannot get through a slow link in time
• Confidentiality: processing in the field and sending only results reduces the chance of a leak

size_gb, link_mbps = 20, 20
seconds = size_gb * 1e9 * 8 / (link_mbps * 1e6)
print(f"raw images: {seconds:.0f} s = {seconds / 3600:.2f} h")

summary_mb = 2
print(f"summary map: {summary_mb * 1e6 * 8 / (link_mbps * 1e6):.1f} s")

raw images: 8000 s = 2.22 h
summary map: 0.8 s

The CIA triad and threats

FIPS 199 sets three security objectives for information, often abbreviated CIA:

• Confidentiality: only authorised people can access the data. A common threat is eavesdropping, such as capturing unencrypted MQTT messages.
• Integrity: data is not changed without authorisation. Threats include spoofing and tampering, such as sending a fake land command.
• Availability: data and systems work when needed. The threat is denial of service, such as flooding a broker with messages or jamming the radio.

A man-in-the-middle attacker sits between two parties and can both read and alter messages, so it threatens confidentiality and integrity at once.

Four tools with different jobs

A hash alone does not stop forgery, because an attacker can change the message and compute a new hash, just like the CRC in module 1. You need a secret key that only sender and receiver hold, which is the idea behind HMAC.

import hashlib

data = b"survey-2026-03-14 block A"
print(hashlib.sha256(data).hexdigest())
print(hashlib.sha256(data + b".").hexdigest())

b21608ab42dbadc11aaa88cfa95b9091bdf336846eb77a47594b2dc542947fd7
961f9721b96b2c3a4515d019d3722e054e4cf7648c89fd804772e69eacb530a0

Adding a single full stop changes the whole hash. In practice, make a list of hashes of every image file before sending and check them again at the destination; a mismatch means a file was damaged or altered.

import hmac
import secrets

key = secrets.token_bytes(32)
command = b'{"cmd":"RTL","drone":3}'
tag = hmac.new(key, command, hashlib.sha256).digest()

forged = b'{"cmd":"LAND","drone":3}'
print(len(tag), "byte tag")
print("genuine command accepted:", hmac.compare_digest(tag, hmac.new(key, command, hashlib.sha256).digest()))
print("forged command accepted:", hmac.compare_digest(tag, hmac.new(key, forged, hashlib.sha256).digest()))

32 byte tag
genuine command accepted: True
forged command accepted: False

NIST CSF 2.0 and the data life cycle

The NIST Cybersecurity Framework 2.0 (February 2024) organises cybersecurity into six functions, with Govern at the centre setting policy, roles and responsibilities.

For IoT device makers, NIST IR 8259 Rev. 1 (April 2026, replacing the 2020 edition) describes the cybersecurity activities to carry out both before and after a product is sold. It is a useful checklist when buying drones or sensors.

Every mission dataset should have a clear life cycle, as in the drone knowledge hub unit on planning the data cycle before collecting drone images.

Module lab

Common mistakes

Summary

• NIST’s cloud definition has five characteristics, the IaaS, PaaS and SaaS service models, and four deployment models
• The edge suits fast-response, large or confidential data; calculate transfer time with $t=8S/R$ before deciding
• CIA stands for confidentiality, integrity and availability; encryption protects confidentiality, while HMAC and signatures protect integrity and prove the source
• NIST CSF 2.0 has six functions with Govern at the centre, and every dataset needs a clear life cycle and owner

Check your understanding

1. Using an online mapping service in a web browser with nothing to install is which service model?
2. How many seconds does a 5 GB file take over a 50 Mbit/s link (ignoring headers)?
3. An attacker replays an old MAVLink message they recorded. Which part of MAVLink signing stops this?
4. Eavesdropping on unencrypted MQTT threatens which CIA objective most?
5. Which NIST CSF 2.0 function covers setting policy and responsibilities?