Your payment tracking number and security key are found on your EOB. The format of the Security Key should be letter / number / letter / number .... (ex A1B2C3...) Your Tax Identification Number (TIN) can be your Employer Identification Number (EIN) formatted as XX-XXXXXXX or your Social Security Number (SSN) formatted as XXX-XX-XXXX, whichever one that was used when the claim was filed.