We have an RSA public$-$key cryptosystem with Bob$$s public key: $($N$=143,$ e$=7)$ and

Alice$$s public key: $($N$=39,$ e$=5).$ Show your work in detail completely

Bob wants to sign a message $($M $=3),$ then encrypt it $($using Alice$$s public key$)$ and send

it to Alice.

Explain the whole process and calculations, and find all the numbers, such as:

Bob$$s task:

a$.$ Sign a message and calculate the signature value

b$.$ Encrypt signature value $($using Alice$$s public key$)$

Alice$$s task:

c$.$ Decrypt the received encrypted signature

d$.$ Verify the signature and signer identity