Question about unique-codes

[gdebrauwer]

Indeed, m and x must be coprimes. You could use 2 non-prime numbers that are coprimes, but it's easier to just use 2 prime numbers. 2 prime numbers are always coprimes :)

[gravataLonga]

Sorry I'm not expertise on math. So, are you telling me that two primes number it's always a coprimes?

[gdebrauwer]

Yes, coprimes are numbers that only have 1 as a common divisor. (For example, numbers 14 and 25 are coprimes, while 14 and 21 are not). A prime number is already a number that only has 1 as a divisor, so that means 2 prime numbers are always coprime to each other.