The Role of BIN (Bank Identification Number) Numbers in Payment Systems

[Cloned Boy]

Educational analysis to understand payment systems and protect against fraud.

1. What is a BIN number?​

BIN (Bank Identification Number) is the first 6-8 digits of the bank card number, which identify:

• Issuing bank (for example, 4276 29 → Sberbank).
• Card type (debit/credit, Visa/Mastercard).
• Card level (Classic, Gold, Platinum).
• Country of manufacture.

Example:

• Card 4147 2020 1234 5678 → BIN 414720 → Bank of America (Visa Platinum, USA).

2. How is BIN used in payment systems?​

2.1. Transaction authorization​

• When paying online, the system checks the BIN to:
  • Determine the issuing bank for the authorization request.
  • Check the country of the card (if the store restricts regions).

2.2. Security and antifraud​

• Fraud check:
  • If BIN 414720 (USA), and IP address from Nigeria → risk of blocking.
  • Services like MaxMind and Sift analyze BIN to detect anomalies.
• Blocking stop-list BINs:
  • Some BINs are known to scammers (for example, prepaid cards).

2.3. Determination of commissions​

• International payments: BIN helps calculate conversion fees (e.g. ruble card in the Eurozone).

3. Where to find BIN databases? (Legal sources)​

For research and development:

1. Official APIs:
   • Binlist.net (free API for checking BIN).
   • Visa/Mastercard BIN Lookup (for payment system partners).
2. Open bases:
   • GitHub repositories with anonymized BINs (e.g. binlist-data).
3. Payment gateways:
   • Stripe, PayPal provide BIN data for integrations.

Example of a request to the Binlist API:

curl https://lookup.binlist.net/414720

Answer:

{
"bank": "Bank of America",
"card_type": "debit",
"country": "US"
}

4. How do scammers use BIN? (For protection, not attacks! )​

1. BIN Attacks:
   • Selection of card numbers in the BIN range (for example, 414720XXXXXX).
   • Security: Limits on input attempts, CAPTCHA.
2. Bypass geoblocks:
   • Use the BIN of the desired country to access content.
   • Protection: Additional IP/geolocation check.

5. How do companies protect themselves?​

• BIN filters: Blocking suspicious ranges.
• Dynamic BIN analysis:
  • Comparing BIN with user behavior (e.g. new BIN + sudden purchases = risk).
• EMV 3-D Secure: Additional authentication for unknown BINs.

6. Interesting facts​

• BIN for virtual cards: Often start with 4 (Visa) or 5 (Mastercard).
• Special BINs:
  • 604001 — UnionPay cards.
  • 3 — American Express (AMEX).

Conclusion​

BIN is a critical element of payment systems used for:
Card identification (bank, type, country).
Security (anti-fraud, fraud blocking).
Commission calculation.

For legal study:

• Use Binlist API.
• Learn PCI DSS (Card Data Security) standards.
• Analyze open BIN leaks (e.g. on GitHub).

Want to dig deeper into how BIN is related to 3-D Secure or how banks detect BIN attacks? Ask!