Chapter 3 - preliminary concepts Flashcards
1
Q
What are the three identities of a byte?
A
- It’s a string of 8 logical or false values
- It’s an 8 bit binary number
- It’s a representation of some character(e.g., letter, digit, punctuation, part of a logogram)
2
Q
What is a function?
A
- Takes one or more values and returns another values as a result
3
Q
What are the values passed into a function called?
A
- Arguments
4
Q
What is the value returned by a function called?
A
- result
5
Q
If a function is denoted by a symbol what is it called?
A
- An operator
6
Q
If there is one argument for an operator where is the operator placed?
A
- In front of the argument
7
Q
If there are two arguments for an operator where is the operator placed?
A
- In between the arguments
8
Q
If a function contains letters as arguments how are the arguments represented?
A
- arguments are contained in parenthesis and each is separated by a coma
9
Q
What are boolean operators?
A
- Functions that operate on bits that represent truth values
10
Q
What are the properties of the logical ‘not’ operator?
A
- Functions that operate on bits that represent truth values
11
Q
What are the properties of the logical ‘and’ operator?
A
- Functions that operate on bits that represent truth values
12
Q
What are the properties of the logical ‘or’ operator?
A
- Functions that operate on bits that represent truth values
13
Q
What are the properties of the logical ‘or’ operator?
A
- A xor B, is true if exactly one of A or B is true, otherwise it is false
14
Q
How is the logical ‘and’ operator represented?
A
- with the character ‘/\’
15
Q
How is the logical ‘or’ operator represented?
A
- with the character ‘\/’
16
Q
Which operator is used extensively in cryptography?
A
- XOR
17
Q
What is an exponential?
A
- a number that is multiplied by itself a specified number of times
18
Q
How is an exponential expression BE read?
A
- B to the E power
19
Q
Given an exponential expression BE .What is B and E?
A
- ‘B’ is the base and ‘E’ is the exponent
20
Q
If N is any number then what is N1
A
- it’s the number ‘N’
21
Q
By convention what is N0 given N is non zero
A
- 1
22
Q
By convention what is 00
A
- 0
23
Q
What is meant by writing a decimal number 3456
A
- 3×1000+4×100+5×10+6×1
24
Q
What is exponential representation of a decimal number 3456
A
- 3×103 + 4×102+5×101+6×100
25
What is a way exponents are used in cryptography?
* exponents are used to convert letters to numbers
26
How can large numbers be represented?
* they can be represented in exponential notation
27
What is another term used for exponential notation?
* scientific notation
28
How is 12,300,000 represented in scientific notation?
* 1.23 x 107
29
How are integers \> 1 classified?
* They're either prime or composite numbers
30
When is a number called a composite?
* When the number is a product of two smaller numbers
31
When is a number called a prime?
* When the number is not product of two smaller numbers
32
What number is neither prime or composite?
* 1
33
What is an important property of the number 1?
* It's neither a prime or a composite number
34
What is an important property of prime numbers?
* any number can be written as the product of prime numbers in only one way (aside from the order of the factors)
35
What are the prime factors of a number?
* the set of prime numbers that can evenly divide the number
36
What is an important characteristic of a set of prime factors of an integer?
* the set of prime factors is unique for the integer
37
What is the process of determining the prime factors of an integer?
* Factoring or Factorization
38
What is the term for two numbers that have no prime factors in common?
* They are called coprime
39
What does it mean if two numbers are coprime ?
* They don't have any common prime factors
40
What is another way of saying a number is coprime?
* The number is mutually prime
41
If N is an integer then what two numbers are always coprime?
* N and 1
42
When are N and 0 coprime?
* When N is 1
43
When two numbers are always coprime?
* N and N+1
44
What is the result when two integers are divided?
* A quotient and a remainder
45
Given positive integers A and B. What is the result when dividing A by B?
* A quotient and a remainder
46
Given positive integers A and B. If A is divided by B? What is the term for B
* B is the divisor
47
What is a divisor?
* Given positive integers A and B. If A is divided by B then B is the divisor
48
Given positive integers A and B. If A is divided by B. What is a remainder?
* The remainder is A-QB
49
Given positive integers A and B. If A is divided by B. What is a quotient?
* The quotient Q is the largest number such that Q \* B doesn't exceed A
50
What is modulo arithmetic?
* The study of remainders
51
What is ignored in modulo arithmetic?
* The quotient
52
What is the divisor called in modulo arithmetic?
* The modulus
53
What is the remainder called in modulo arithmetic?
* The residue
54
Given a modulus is N and two numbers X and Y have the same residue what is the term for X and Y
* X and Y are said to be congruent modulo N
55
if X and Y are said to be congruent modulo N what is true
* X and Y both have a modulus of N and they have the same residue
56
if X and Y are said to be congruent modulo N what is true
* X and Y both have a modulus of N and they have the same residue
57
How is it written given X and Y are congruent modulo N
* X ≡ Y Mod(N)
58
What does the expression ‘X mod Y’ do?
* It gives the remainder of dividing X by Y
59
What is the additive inverse of a number A?
* It's the opposite of the number A
60
If you add a number with it's additive inverse what do you get?
* 0
61
What is the multiplicative inverse of a number?
* It's the inverse of the number
62
What do you get if you multiply a non-zero number by it's multiplicative inverse?
* 1
