An RSA algorithm uses $247$ as a modulus. The public key for this

algorithm is given by:

$($a$)(7,247)($b$)(4,247)($c$)(2,247)($d$)(3,247)$

The calculated private key Ks is given by:

$($b$)(200,247)($b$)(22,221)($c$)(17,247)($d$)$ neither a$,$ b or c

For the character B$=66$ the cypher text is given by:

$($a$)51$

$($b$)118($c$)13($d$)19$

For the numerical character $250$ the cypher text is given by:

$($a$)250$

$($b$)20($c$)247($d$)$ neither a$,$ b$,$ or c

Alice uses an RSA algorithm with the private key Ks and the public

key KP given by $(5,247)$ and $(21,247)$ respectively.

Alice wants to sign a contract before sending it to her lawyer. The key

Alice must use is given by:

$($a$)(4,247)($b$)(5,247)($c$)(21,247)($d$)(3,247)$

Alice$$s lawyer uses an RSA algorithm with the private key Ks and the

public key KP given by $(3,247)$ and $(11,247)$ respectively.

Alice is worried about an unauthorised person gaining access to her

documents during transmission. Alice decided to double encrypt her

document using the following keys and order:

$($a$)(5,247),(11,247)($b$)(21,247),(3,247)($c$)(21,247),(11,247)$

$($d$)(3,247),(11,247)$

In applications which require the use of public and private key

encryption algorithms,

$($a$)$ both public key and private key are used for encryption $($b$)$

private key is used for key distribution and pubic key is used for

encryption $($c$)$ Public key is used for key distribution and private key

for encryption $($d$)$ both public key and private key are used for key

distribution