The RSA Cryptosystem $2$

Consider a public key cryptosystem. The public encoding function is: $E(x)-=x^7(mod15).$

The two prime numbers that are kept private for your public key crypto system are: $p=3,q=5$

To find the decoding power we need to find the inverse of $,$ in mod$(p-1)(q-1)=$

The decoding function is: $D(x)-=x^{,}(mod15)$

Decode the cipher text:GLCMCHG

Use the following table to convert mod $15$ remainders to letters:

"The World Altitude Record for gliders currently stands at $50,699$ft$,$ achieved above the Andes by Steve

Fossett in $2006.$ This is higher even than most long$-$haul flights! The air at that altitude is incredibly thin,

requiring oxygen masks to be worn, and incredibly cold $-$ and remember that gliders don't have heaters!

The World Record for the longest glider flight is a whopping $56$ hours and $15$ minutes, achieved in France

in $1952$ by Charles Atger." $-$ Air Experiences

A

B

C

D

E

$F$

G

I

$J$

$K$

M

$P$

$S$

Z

$0$

$1$

$2$

$3$

$4$

$5$

$6$

$7$

$8$

$9$

$10$