Cryptography 6

Question 1

If there is a single bit failure, then the error-correcting code will detect and correct the error.

*** Standard implementation techniques are entirely inadequate to create secure code.

*** certain attacks are impossible if you use real random data.

*** a|b and b|c then a|c

Answer 1

ECC (error-correcting code) memory Etc …

Question 2

divide the system into separate modules, and design, analyze, and implement each module separately.

Answer 2

Modularization

Question 3

are a real danger to smart cards because the card is under full control of the adversary, but only a few types of side channels are practical against most other computers. In practice, the most important side channels are timing and RF emissions. (Smart cards are particularly vulnerable to measuring the power consumption).

Answer 3

Side Channels

Question 4

is not really random at all. It is generated from a seed by a deterministic algorithm. If you know the seed, you can predict the pseudorandom data. Traditional pseudorandom number generators, or PRNGs, are not secure against a clever adversary. They are designed to eliminate statistical artifacts, not to withstand an intelligent attacker.

Answer 4

Pseudorandom data

Question 5

The generator takes a fixed-size seed and generates arbitrary amounts of pseudorandom data. The accumulator collects and pools entropy from various sources and occasionally reseeds the generator. Finally, the seed file control ensures that the PRNG can generate random data even when the computer has just booted.

*** The accumulator collects real random data from various sources and uses it to reseed the generator.

Answer 5

Fortuna Etc …

Question 6

Let n be a positive number greater than 1. Let d be the smallest divisor of n that is greater than 1. Then d is prime.

group is simply a set of numbers together with an operation, such as addition or multiplication. A subgroup consists of some of the elements of the full group.

Answer 6

numbers …

Question 7

Ethics, Reputation, Law, Physical Threat, MAD = threat to do harm to both yourself and the other party.

Answer 7

Sources of Trust

Question 8

The receiver must be able to parse the message, which looks like a sequence of bytes, back into its constituent fields. This parsing must not depend on contextual information.

Answer 8

Parsing

Question 9

Even knowing personA authentication key doesn’t let the attacker find the session key k for a protocol that has already finished, even if the attacker recorded all the messages.

Answer 9

Forward Secrecy

Question 10

wooping is to verify a computation modulo a randomly chosen small prime.

Protocol identifier Identifies exactly which protocol and protocol version this is. Version identifiers are important.

Answer 10

info …