Use the R$5$A cipher with public ker $[pq,e)=(23-31,43]=(713,43)$ and private kery $,d,$ where $d=307,$ to decrypt the glven ciphertext and find the original message. $($Assume the letters of the alphabet are encoded as foliows:

$A=01,B=02,C-03,$dots,$z-26$

Since $d-307=256+32+16+2+1,$ find the first letter of the decryped message by computing ${675}^d$ mod $713.$ Niow

${675}^1=a(mod713){675}^2=b(mod713){675}^4=c(mod713)$

${675}^8=d(mod713){675}^{16}=c(mad713){675}^{32}=r(mod713)$

${675}^{64}=g(mod713){675}^{128}=h[mad713){675}^{256}=i(mod713).$

Thus, ${675}^{307}$ mod $713=(a*b-e*f-i)mod713=,$ and so the first letter in the encrypted message is is $x.$

Repeat these computations for each wentrypted letter and find the completed ducrypted message.