custom cipher:
consists of two parts 1st encryption using HEN encryption algorithm and then encode using a standard alphmetic puzzle

the stardard alphametic puzzle used is {ZCUKZ+NPYFG=GFUKPH}

HEN encryption:

'size of plaintext' is number of alphabets in plaintext

Multiply the position of alphabet (starting with one) with 'size of plaintext'  and do mod 26.
now left shift the PT every alphabet with their corresponding value 


Example for HEN encryption scheme:

Plaintext : I_AM
Size of plaintext : 3
Ciphertext: F_UD