Cryptography and Society Flashcards
What are the two kinds of encryption?
Asymmetric encryption
Symmetric encryption
What is Symmetric Encryption?
Encryption and decryption are done with the same shared key.
i.e. in Caesar cipher: if the key = 5,
ABC becomes FGH, and you use the same key to decrypt
What is Asymmetric Encryption?
Encryption is done with the PUBLIC KEY of the receiver
Decryption is done with the PRIVATE KEY of the receiver
How are public and private keys made?
1) choose two large primes, π and π;
2) calculate π = π Γ π;
3) calculate π§ = (π β 1) Γ (π β 1);
4) choose π to be relatively prime to π§*;
5) choose π such that (π Γ π) mod π§ = 1.
The public key is (π, π); the private key is (π, π).
*Two numbers are relatively prime if they have no common factors other than 1.
Formula for Asymmetric Encryption
πΆ = π^π mod π
ciphertext C
plaintext M
Formula for Asymmetric Decryption
π = πΆ^d mod π
ciphertext C
plaintext M
Arguments for Encryption
Allows good people to go about their legitimate business without government surveillance (Orwellian society)
Arguments against Encryption
Allows bad people to go about nefarious business without detection by government
What is Zimmermanβs Law
The idea that the ability of computers to track us doubles every eighteen months.
What did Ed Snowden reveal?
Mass surveillance by the US NSA of network links and attempts to weaken encryption.
What does the Internet Goes Dark mean?
Where HTTPS was implemented and all data was encrypted, meaning it was hidden from the NSA.
What is End to End encryption?
The software creates the encryption and decryption keys. Only the sender and receiver can read the messages, not even internet providers or the service it was sent on i.e. WhatsApp
Why did the Department of Justice issue an investigation into Phil Zimmermannβs activities?
His PGP program used 128-bit keys.
