Working random IBAN generation for France

[nvuillam]

For French IBANs, there can be different consistency checks

• Existing BankCode
• Existing BrancheCode
• Consistency of FR nationalCheckDigit

So random generated IBANs with Country.FR are not valid.

Here is a workaround for anyone looking for it ( maybe you can integrate it in your library if you like )

      String bankCode = "30006" ;
      String branchCode = "00001" ;
      Random r = new Random();
      int Low = 10;
      int High = 1000000;
      int AccountNumberInt = r.nextInt(High-Low) + Low;
      String AccountNumberStr = String.valueOf(AccountNumberInt);
      String AccountNumber = StringUtils.repeat("0", 11 - AccountNumberStr.length()) + AccountNumberStr;
      long a100000000000 =  (long) 100000000000.0;
      Long nationalCheckDigitInt = 97 - (((Long.valueOf(bankCode) % 97 * 100000 + Integer.valueOf(branchCode)) % 97 * a100000000000 + Integer.valueOf(AccountNumber)) % 97) * 100 % 97;
       String nationalCheckDigit = String.valueOf(nationalCheckDigitInt) ;
       Iban iban = new Iban.Builder().countryCode(CountryCode.FR).bankCode(bankCode).branchCode(branchCode).accountNumber(AccountNumber).nationalCheckDigit(nationalCheckDigit).buildRandom();  

[thecoder8890]

This is more effective

String bankCode = "30006" ; String branchCode = "00001" ; Random r = new Random(); int Low = 10; int High = 1000000; int AccountNumberInt = r.nextInt(High-Low) + Low; String AccountNumberStr = String.valueOf(AccountNumberInt); String AccountNumber = StringUtils.repeat("0", 11 - AccountNumberStr.length()) + AccountNumberStr; long a100000000000 = (long) 100000000000.0; Long nationalCheckDigitInt = 97 - (((Long.valueOf(bankCode) % 97 * 100000 + Integer.valueOf(branchCode)) % 97 * a100000000000 + Long.valueOf(AccountNumber)) % 97) * 100 % 97; String nationalCheckDigit = String.valueOf(nationalCheckDigitInt) ; Iban iban = new Iban.Builder().countryCode(CountryCode.FR).bankCode(bankCode).branchCode(branchCode).accountNumber(AccountNumber).nationalCheckDigit(nationalCheckDigit).buildRandom();

[bllakinci]

The basic formula to calculate nationalCheckDigit for FR is like this;

  @param bankCode 5 character
  @param branchCode 5 character
  @param accountNumber 11 character

  cleRibKey = - (bankCode * pow(10,18)  + branchCode * pow(10,13) + accountNumber * pow(10,2))  % 97
  cleRibKey = - (bankCode * 89          + branchCode * 15         + accountNumber * 3)          % 97

If you want to create an account number that contains letters you need to replace characters in the account number with the below numbers. After that, you can calculate the cleRibKey with the above formula.

A, J = 1
B, K, S = 2
C, L, T = 3
D, M, U = 4
E, N, V = 5
F, O, W = 6
G, P, X = 7
H, Q, Y = 8
I, R, Z = 9