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COMP6441 - Coggle Diagram
COMP6441
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Hashing
Like encryption, but different sized output.
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2nd Preimage resistance: finding a collision.
Done via a birthday attack (square root rule, takes the square root of the number of bits).
Secrets
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Military ciphers
- System must be practically indecipherable
- The process is not secret
- Key must be communicable and retainable
- Must be applicable to telegraphic correspondance
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Brute force attacks
On average, will guess correctly halfway through the total space of possibilities
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Privacy
Information
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Data wants to be free, because of the increase in value
Privacy Forward Property: once data is released it can't be retracted. Should think about future use of the data when you release it.
Deidentifying: data can be 'deidenitfied' by removing some aspects of the information. But this can be compared against other data, reidentifying it.
Impossible goal
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Safety vs Security
Safety is similar to engineering, as they are trying to prevent incidents as well.
Encoding bias: we don't accept some information if it doesn't fit our mental model. We filter it out
Hindsight Bias: events that happened before an event are understood as the cause, even if they are unrelated
The difference is that security is about an adversary, safety is about random chance.
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A good solution to safety, to avoid human error, is to have a culture of safety. Don't punish those who get it wrong.
Ciphers/Encryption
Symmetric
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Transposition
Permutate the order, can be via a keyword
One Time Pad
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Use once, or else the pattern can be determined
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Authentication
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Computer has very limited senses, so much harder to authenticate.
Generally need to compare a shared secret, like a password.
Man in the middle attacks use this, passing on the shared secret.
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Humans
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Trust
People have a tendency to trust, and will overlook logic for trust
Risk
Humans judge risk off past frequency. We are bad at assessing low probability situations. However, inevitably things will occur.
We have cognitive biases that changes how we see things.
Confirmation Bias: favour information that confirms previous beliefs.
Security is about defending high impact, low probability situations.
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Assets
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How to value assets:
- Survey as many people as you can. The group always had a better idea.
OpSec
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How to remain anonymous
VPNs: disguises yourself but also reveals more nefarious intentions, and people do nefarious things through a VPN. People can watch the VPN and track you that way.
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Good OpSec
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Fails closes: fails into a defended, safe state, not vulnerable.
Layers
- We don't know anything is happening.
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- We know something happened, but not who.
Caught via honeypots, or not bouncing around enough.
- We know someone by the name 'bartman' did it.
Persona management is important, don't link your persona to your identity.
Distinguishable by grammar, punctuation.
You can be famous or a hacker, but not both.
- We actually know their identity.
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Mitnick's Attack
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Adds his own computer to the permission list, installing a backdoor for himself.
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Incident Response
About considering high impact, low probability events.
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Errors
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Always trying to minimise both, but have to decide which is worse
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Command and Control
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Options
One person at the top in charge, operating on a chain of command.
Everyone equal, promoting more creativity but lower power for each.
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Dual Control: Two elements must be in sync, for both redundancy and to see if a situation is wrong.
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Communication
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Tips
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No acronyms, makes people feel left out when they don't know them.
Hypnotising Chickens
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Attention is a scarce resource, assume you only have it briefly.
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Sovereignty
Should you own and produce everything yourself, or should you outsource.
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On the other hand, you shouldn't roll your own.
Cyber Crime
WannaCry: A cryptoworm, ransomware
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NotPetya: pretended to be ransomware, just destroyed the data. Used a wateringhole attack (hit a common service that people visit regularly).
Insider Threats
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Motivations
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Morals: Whistleblowers
Hard to defend against, cultural issue.
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Zero Knowledge Protocol
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Often probability based, proving beyond doubt. Proving that they couldn't randomly guess it.
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Blockchain
Proof by work. It takes up to 10min to produce a new block onto the blockchain. That workpower, once more blocks have been created, forms a permanent record.
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Cyber War
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Countries fighting against one another. Considered to be the 5th domain. Huge amount of resources can be pooled for this
Measuring
Information
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Bits of Information
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Alternative means choice in question, not per letter