[PhilipRoman]

I really like the concept of adding some redundancy to ids, like a prefix. It helps to disambiguate things (kind of like static typing). A good example is also bank numbers, which must be a multiple of 97 +1, enabling fast client-side validation against typos.

[cupantae]

Could you give a reference on this 97 rule? I’m intrigued.

[az09mugen]

I was also intrigued, so I searched and on wikipedia ( https://en.wikipedia.org/wiki/International_Bank_Account_Num... ), in the section "Validating the IBAN" it is written :

    Interpret the string as a decimal integer and compute the remainder of that number on division by 97
    If the remainder is 1, the check digit test is passed and the IBAN might be valid