For the symmetric-key encryption algorithm, is it possible to use the exponent and modulo to be the keys For example:

Encrypt with: $M^{k_1} \bmod k_2$ 

where $M$ is message, $k_1$ and $k_2$ are independent keys

If it is possible, what is the decryption algorithm?

Thanks!
I don't think 'mod' can be reversed, so it is not possible.
Consider k1 = 2, k2 = 6.
Now,
M = 1 => C (ciphertext) = 1.
M = 5 => C = 1  

You have no way of knowing whether the cleartext was 1 or 5, as you get the same ciphertext for both.