please write in C

a). A function to encrypt the message

b). A function to decrypt the message program to encrypt and decrypt a string using Caesar Cipher method

2.

a).A function int gcd(int a, int h) to calculate gcd of e and totient and

b).Program to encrypt and decrypt the data using RSA algorithm

1 2 3 C program to encrypt and decrypt the data using RSA algorithm #include #include 5 6 7 8 // to find god int gcd(int numi, int num2) { [/write your code here } 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 int main() { 1/2 random prime numbers double p - 13; double q- 11; double nep*a; double count; double totient = (p-1)*(-1); 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 1/public key encryption. check 11 while(e