Social + Professional Flashcards
First Generation - period
1950-1959
Second Generation - Period
1960-1968
Thrid Generation - Period
1969-1977
Fourth Generation - Period
1978-2009
Fifth Generation - Period
2010-Now
First Generation - Innovation
Vacuum Tube
Second Generation - Innovation
Transistor
Third Generation - Innovation
Integrated Circuit
Fourth Generation - Innovation
Microprocessor
Fifth Generation - Innovation
SoC - System on Chip
Wheel of Reincarnation
Technology goes out of fashion then comes back
2 kinds of encryption
Symmetric and Asymmetric
Symmetric encryption + example of use
Encryption and deception with the same shared key.
Examples:
Ceasear cipher
AES - Advanced Encryption Standard
Communication after keys transferred with asymmetric (e.g. WhatsApp)
Asymmetric encryption + example of use
Encryption with the receivers public key, decryption with the receivers private key
Examples:
Initial key transfer for communication (e.g. WhatsApp)
Bank transactions
How does Asymmetric encryption solve key distribution problem?
Key distribution problem - can’t share encryption keys in safe/encrypted way because you would need encryption already established
Hence - asymmetric encryption used just to send encryption key (since it’s safe), then key used for symmetric encryption (since it’s cheaper)
Setup, encryption and decryption for asymmetric
Setup: 1. 2 large primes, p and q 2. n = p x q 3. z = (p-1) x (q-1) 4. Choose e to be relatively prime to z (no common factors) 5. Choose d such that (d x e) mod z = 1 Public key = (e,n) Private key = (d,n)
Encryption:
M = plaintext
C = ciphertext
C = M^e mod n
Decryption:
M = C^d mod n
Argument for encryption
Allows good people to go about there business without government surveillance or criminal hacking
Argument against encryption
Allows bad people to do bad things without government detection
What is PGP
PGP is Pretty Good Privacy
128 bit encryption free for all in 1991
Snowden Report
Ed Snowden revealed mass surveillence by US NSA
Google, Yahoo and other companies started using strong encryption in responce (http -> https) - The internet goes dark
Fiat Currency
Any money declared by a government to be legal tender
Cryptocurrency
A decentralized digital medium of
exchange, governed by cryptography
- Digital currency
Safety of fiat currency/risk with cryptocurrency
Hard to forge or double-spend metals or tokens
which are physical (fiat) money, but easy for electronic money.
Almost all fiat currency transactions go through a trusted third party (multiple banks) which use a shared register
Hash function + 3 benefits
A hash function takes a string, 𝑀, and returns a number,
𝐻(𝑀).
One-way - easy to generate H(M) but hard to go back
Leakage free - hard to find out anything about M from H(M)
Collision free - hard to find W such that H(W) = H(M)
Cryptocurrency trusted 3rd party
Blockchain
- ledger maintained by many, untrusted nodes
3 points blockchain is based on
Transactions
Extension
Mining
Blockchain - transactions
Transactions - a transaction is sent to one of the nodes maintaining the ledger, and the node passes it on
Blockchain - extension
Extension - node may attempt to extend the blockchain with a batch of transactions for a reward. New blocks flooded to nodes and nodes add to blocks which make the longest chain
Blockchain - mining
Mining - A nonce (number-used-once) is chosen for each block, so that its hash is less than the current threshold.
Cryptocurrency wallet
A public key to allow it to receive payments from other wallets, and a private key to allow it to make payments to other wallets
Advantage of cryptocurrency
Allows people to store money and make payments without money devaluation
Disadvantage of cryptocurrency
Allows people to store money and make payments without getting taxed
4 laws relating to intellectual property
Copyright
Trademarks
Patents
Trade secrets
Copyright law
Gives the creator of a work the right to control how it is used. Applies to work, not the idea behind it. Can copyright ‘Pride and Prejudice’ but not romantic novel in general. Automatically valid when a work is created and lasts for 70 years