Network Security
Q26.
The total number of keys required for a set of n individuals to be able to communicate with each other using secret key and public key cryptosystems, respectively are:Q27.
In the RSA public key cryptosystem, the private and public keys are (e,n) and (d,n) respectively, where n=p*q and p and q are large primes. Besides, n is public and p and q are private. Let M be an integer such that 0 \lt M \lt n and \phi (n)= (p-1)(q-1). Now consider the following equations. I. M'=M^{e} mod \; n M=(M')^{d}mod \; n II. ed=1 mod n III. ed=1 mod \phi (n) IV. M'=M^{e}mod \; \phi (n) M=(M')^{d}mod \; \phi (n) Which of the above equations correctly represent RSA cryptosystem?Q30.
Consider the following two statements: i.A hash function (these are often used for computing digital signatures) is an injective function. ii.A. encryption technique such as DES performs a permutation on the elements of its input alphabet. Which one of the following options is valid for the above two statements?