I need to repost my last comment. I am stuck on this question and I can not find any references on how to do this. Why? Because it was not taught. So I sent a message to my online teacher with no reply so please help:
A cetain encryption algorithm, applicable to totally numerical (decimal) messages, creates a ciphertext that relates to the plaintext as follows: Ciphertext Part One = INT[SQRT(Plaintext)]
Ciphertext Part Two = Plaintext – {INT[SQRT(Plaintext)]}^2
a. Determine the plaintext if the ciphertext is: Part One= 28 and Part Two=5
INT[SQRT(28)] =5
Plaintext – {INT[SQRT(Plaintext)]}^2
b. Determine the two parts of the ciphertext if the plaintext is 123456
+118653 
