CFLib.org – Common Function Library Project

Description:
Validates an IBAN number.

Return Values:
Returns a boolean.

Example:

<cfoutput>#validateIBAN("NL60INGB0006155045")#</cfoutput><!--- this is a valid IBAN --->
<br />
<cfoutput>#validateIBAN("NL58INGA0006155031")#</cfoutput><!--- an invalid IBAN --->

Parameters:

Full UDF Source:

<!---
Validates an IBAN number.

@param IBANnr IBAN input (Required)
@author Hank van Empel (h.vanempel@s-hertogenbosch.nl)
@version 1.0, January 7, 2015
--->
<cffunction name="validateIBAN" returntype="boolean" output="no">
    <cfargument name="IBANnr" required="Yes" type="string" /> <!--- input IBAN --->
    <cfset var ci = structNew() />

    <!--- remove spaces first from input-IBAN --->
    <cfset arguments.IBANnr = replaceNoCase(arguments.IBANnr," ","","ALL") />

    <!--- after spaces are removed, we can do a syntaxcheck, IE. "NL60INGB0001234567" --->
    <cfset ci.syntaxCheck = REFind("[A-Z]{2}[0-9]{2}[A-Z]{4}[0-9]{4}[0-9]{4}[0-9]{2}", arguments.IBANnr) />

    <cfif ci.syntaxCheck>
        <cfset ci.IBANnr = arguments.IBANnr />    
        <cfset ci.Result = ci.IBANnr />
    <cfelse> <!--- IBAN failed the syntax-check, so return False --->
        <cfreturn false />
    </cfif>

    <!--- our example is "NL60INGB0001234567" --->
    <!--- where "NL" is the country-code
                                       "60" is our control-number
                                       "INGB" is our bank-code
                                       "0001234567" is our accountnumber --->
    <!--- !!! our example is NOT a valid IBAN by the way --->                                  

    
    <!--- determine controlnumber; we will use this later on (in our example: "60")--->        
    <cfset ci.submittdeControlNumber = mid(ci.IBANnr, 3, 2) />
    <!--- get first 2 characters, they represent the country-code (in our example: "NL") --->
    <cfset ci.Landcode = left(ci.IBANnr, 2) />

    <!--- turn these characters ("NL" in our example) into digits where A=10, B=11 etc. --->
    <!--- to do so we subtract 55 from the character's ASCII-value --->
    <!--- remember, these have to be uppercase --->
    <!--- Example: "AB" becomes 1011, "NL" becomes 2321 --->
    <cfset ci.countryDigits = ((asc(left(ci.Landcode,1))-55)*100) + (asc(right(ci.Landcode,1))-55) /> 

    <!--- add 2 zeroes and convert to numeric at the same time by multiplying it with 100--->
    <cfset ci.countryDigits = ci.countryDigits * 100 />

    <!--- get the bankcode, in this example "INGB"  (A=10, B=11 etc.) --->
    <cfset ci.Bankcode = Mid(ci.IBANnr, 5, 4 ) />

    <!--- convert to digits, where (A=10, B=11 etc.) --->
    <!--- IE. "INGB" becomes 18231611 --->
    <cfset ci.bankDigits = (asc(left(ci.Bankcode, 1)) - 55) & (asc(Mid(ci.Bankcode, 2, 1)) - 55) & (asc(Mid(ci.Bankcode, 3, 1)) - 55) & (asc(Mid(ci.Bankcode, 4, 1)) - 55) />

    <!--- replace the bankcode by it's numeric value (ASCII-value minus 55, for each character)
    IE. "INGB" will become "18231611" --->
   <cfset ci.IBANnr = replace(ci.IBANnr, ci.bankcode, ci.bankDigits, "ONE") />

    <!--- remove the bankcode and the controlnumber, in our case "NL60" --->
    <cfset ci.IBANnr = Right(ci.IBANnr, Len(ci.IBANnr) -4) />

     <!--- concatenate the numbervalue that represents the
    bankname (in this example "INGB") to the accountnumber --->
    <cfset ci.IBANString = ci.IBANnr & ci.countryDigits />

    <!--- create a Java.BigDecimal because CF cannot handle such a big number
               in our example that would be 182316110003770857232100 --->
    <cfset ci.bigInt = createObject("java", "java.math.BigDecimal").init(javaCast("string", ci.IBANnr&ci.countryDigits)) />

    <!--- all other component have to have the same cast: bigdecimal --->
    <cfset ci.baseNumber = createObject("java", "java.math.BigDecimal").init(javaCast("string", "98" )) />
    <cfset ci.divider = createObject("java", "java.math.BigDecimal").init(javaCast("string", "97" )) />

    <!--- take the baseNumber and subtract the remainder after divide by 97--->
    <cfset ci.remainder = ci.baseNumber - ci.bigInt.remainder(ci.divider) />

    <!--- return True if the remainder matches the controlNumber (56 in this example) --->
    <cfif ci.submittdeControlNumber EQ ci.remainder>
       <cfreturn true />
    <cfelse>
        <cfreturn false />
    </cfif>

</cffunction>