Question

Answer the following questions.

a. What does it mean to say that b is a divisor of a?
b. What is the meaning of the expression a divides b?
c. What is the Congruent Modulo n ? Support your answer with one example of Congruent Modulo n.
d. What is a prime number? Support your answer with one example of two integers are relatively prime.
e. What is the difference between active and passive attacks?

Answer 1

a) It means that we can divide a by b.

For example consider the case 6/3 . Here 3 is the divisor and using the divisor 3 we are dividing the divident 6.

b)The expression a divides b specifically means that we can divide b by a and when we does it so we get no remainder ,that is the remainder will be zero and also there will be a quotient q such that by using the formula

a(divisor)*q(quotient)+0(remainder)=b(divident)

i.e a*q=b

c)Congruent Modulo n .

Two numbers p and q are said to satisfy this congruent modulo n property when we can divide the dfifference formed by p and q is divisible by n.

For eg: Let n =2 p=6 and q=4. Here p-q=2 and it is divisible by n and so it satisfies the congruent modulo property.

d)Prime numbers are numbers for which there will be only two numbers as factors.The two numbers will be 1 and the number itself

We can say two numbers are relatively prime when the HCF of two numbers is 1.

For eg: Take the example of 5 and 7. Here the HCF of these two numbers is 1 and so they are relatively prime.

e)Passive attacks mainly deals with the collecting of datas ,messages,valuable credentials etc and these data's are used in active attacks

While in active attack the datas,messages etc collected in the passive attack phase will be made use for attacks.

Hope this helps!!!