0 votes 0 votes Using RSA key crypto system with a = 1, b = 2 etc; value for encryption if prime value are p = 7 and q = 11, the legal value for secret key is . a)69 b)49 c)49 d)119 Computer Networks cryptography network-security computer-networks + – Shivangi Parashar 2 asked Oct 12, 2018 Shivangi Parashar 2 1.2k views answer comment Share Follow See all 5 Comments See all 5 5 Comments reply Mk Utkarsh commented Oct 12, 2018 reply Follow Share both c and b options are 49? 0 votes 0 votes Prateek Raghuvanshi commented Oct 12, 2018 reply Follow Share i think 49 will be the answer three condition should be follow to choose key (1) n=p*q=7*11 n=77 (2) Euler Totient function $\phi(n)=(p-1)(q-1)${if p and q are prime numbers} $\phi(n) =6*10=60$ (3) now choose e such that 1<e<$\phi(n) $ and e and $\phi(n) $ should be coprime means GCD(e,$\phi(n) $)=1 by seeing option only 49 is satisfying the condition because 49 is less than 60 and also GCD(49,60)=1 then (e,n) will be used as public key which will be used to encrypt the message . 0 votes 0 votes Mk Utkarsh commented Oct 12, 2018 reply Follow Share Prateek but u calculated e? 0 votes 0 votes Prateek Raghuvanshi commented Oct 12, 2018 reply Follow Share Yeah you are right ,I think question is about e otherwise i don't know what is mean by secret key 0 votes 0 votes altamash commented Dec 8, 2018 reply Follow Share question is about to find d,not secret key but five legal values.for d 0 votes 0 votes Please log in or register to add a comment.
0 votes 0 votes i think ans will be 49 vikashbit055 answered Nov 4, 2018 vikashbit055 comment Share Follow See all 0 reply Please log in or register to add a comment.