How to find the key to encrypt text to encryption?

[matija_]

Hello, I have a date with format (dd.mm.yy) and that value represents the code ID.

I want to find the algorithm and a key so I can produce the code for the future dates.

Table of solved solutions looks like this below: (last characters in day ID are censored XX)

day ID      Day (dd.mm.yy)
891383XX 25.01.21
6018EFXX 23.02.21
A38F43XX 25.02.21
2A31ADXX 03.03.21

How should I approach the problem solution?