Electronic Payment Systems & Digital Transactions: Methods, Security & Workflows

Core Concepts: What is an Electronic Payment System?

Electronic Payment Systems (EPS) enable secure, digital transactions between buyers and sellers without physical cash or checks. They rely on:

• Networks (internet, mobile, banking systems)
• Security protocols (encryption, tokens, biometrics)
• Intermediaries (banks, payment gateways like Khalti, eSewa, or PayPal).

How EPS Works: A Step-by-Step Trace

flowchart TD
    A["Buyer Initiates Payment"] -->|"1"| B["Payment Gateway\n(e.g., Khalti API)"]
    B -->|"2"| C["Bank/Payment Processor\n(e.g., NMB Bank)"]
    C -->|"3"| D["Merchant’s Bank Account"]
    D -->|"4"| E["Seller Receives Funds"]
    C -->|"5"| F["Transaction Log\n(Blockchain/Database)"]
    F -->|"6"| G["Confirmation to Buyer"]

Real Example: When you order a Daraz product via Khalti, the payment flow is:

1. You enter your Khalti PIN → Khalti’s server validates it.
2. Khalti deducts funds from your bank account (e.g., NMB) and sends them to Daraz’s bank.
3. Daraz’s system updates your order status to "Paid" and triggers delivery.

Types of Electronic Payment Systems

Key Components of EPS

1. Payment Gateways

• Definition: Middleware that processes transactions (e.g., PayPal, Khalti).
• How It Works:
  1. Merchant’s website redirects to the gateway (e.g., Daraz → Khalti).
  2. Gateway encrypts data (using SSL/TLS) and sends it to the bank.
  3. Bank approves/rejects → gateway sends confirmation to the merchant.

2. Security Protocols

3. Digital Signatures

• Definition: A cryptographic signature that proves a transaction is authentic (e.g., e-signatures for contracts).
• How It Works:
  1. Sender’s private key encrypts a hash of the document.
  2. Recipient uses the sender’s public key to verify.
• Advantages:
  • Prevents repudiation (denying a transaction).
  • Legally binding in Nepal (under Electronic Transactions Act, 2008).
• Disadvantages:
  • Requires PKI (Public Key Infrastructure) setup (expensive for SMEs).

Risks in Electronic Payment Systems

Real Example: eSewa Scam (2021)

• What Happened: Hackers exploited a weakness in eSewa’s API to transfer funds from users’ wallets to their accounts.
• How It Was Fixed: eSewa implemented two-factor authentication (2FA) and transaction limits.

Advantages of EPS Over Traditional Payments

Disadvantages:

• Technical Barriers: Requires internet/smartphone access (challenging in rural Nepal).
• Fees: Transaction charges (e.g., 1.5% on Khalti payments).
• Privacy Concerns: Data shared with banks/payment processors.

Case Study: Online Credit Card Transaction

Scenario: You buy a $50 laptop from Sano using a Global IME debit card.

sequenceDiagram
    participant User
    participant SanoWebsite
    participant KhaltiGateway
    participant GlobalIMEBank
    participant SanoBank

    User->>SanoWebsite: Enters card details (PCI-DSS compliant)
    SanoWebsite->>KhaltiGateway: Sends encrypted data (AES-256)
    KhaltiGateway->>GlobalIMEBank: Requests authorization (3D Secure OTP)
    GlobalIMEBank-->>KhaltiGateway: Approves $50 (PCI DSS compliant)
    KhaltiGateway->>SanoWebsite: Returns "Success" (HMAC signature)
    SanoWebsite->>User: Shows "Payment Approved"
    KhaltiGateway->>GlobalIMEBank: Deducts $50 (real-time)
    GlobalIMEBank->>SanoBank: Transfers funds (Nepal Rastra Bank clearing)

Real Example: NEPSE Stock Trading

• Investors use digital wallets (e.g., Khalti) to buy/sell shares via Merchant Bank’s online platform.
• Security: Transactions are logged on blockchain (for transparency) and verified via OTP.

Emerging Trends in Nepal

1. UPI-like Systems (NEPAY)

   • Nepal Rastra Bank’s NEPAY allows interoperable payments between banks (e.g., transfer from NMB to Standard Chartered).
   • Example: Pay your NTC bill directly from your Global IME account.

2. Biometric Payments

   • Ncell Pay now supports fingerprint authentication for low-value transactions (< Rs. 500).

3. Central Bank Digital Currency (CBDC)

   • Nepal Rastra Bank is exploring a digital rupee to reduce cash dependency.

In the Real World

1. Khalti & eSewa

   • Idea Used: Digital Wallets + Tokenization
   • How: When you pay for a Pathao ride, Khalti generates a one-time token instead of sharing your card details. This reduces fraud risks.

2. Daraz & Sano

   • Idea Used: Payment Gateways + SSL Encryption
   • How: During checkout, Daraz redirects you to Khalti/eSewa, where your payment data is encrypted via TLS 1.3 before reaching the bank.

3. Ncell Pay for Traffic Fines

   • Idea Used: Mobile Banking + USSD
   • How: Instead of visiting a police station, you pay Rs. 1,500 traffic fine via Ncell Pay (9800), which directly transfers funds to the government’s account.

4. Nepal Investment Bank (NIBL) Loans

   • Idea Used: Digital Signatures for Loan Agreements
   • How: Customers e-sign loan documents using NIBL’s e-signature portal, which is legally valid under Nepal’s Electronic Transactions Act.

Exam Tip

1. Diagrams Are Key

   • Always draw flowcharts for:
     • Payment gateway workflows.
     • SSL/TLS encryption steps.
     • Credit card transaction processes.
   • Example Question: "Illustrate the procedure for online credit card transaction." → Use a sequence diagram (like above).

2. Compare EPS vs. Traditional Payments

   • Memorize 3 advantages/disadvantages for each (e.g., EPS = faster, traditional = no internet needed).

3. Real-World Applications

   • Link answers to Nepali examples:
     • "Like Khalti, digital wallets use tokenization to secure transactions."
     • "NEPSE uses blockchain for transparent stock trades."

4. Security Protocols

   • Know the difference between SSL, 3D Secure, and tokenization.
   • Example Answer:

     "SSL encrypts data in transit, while 3D Secure adds an OTP layer for authentication. Tokenization replaces card numbers with random tokens (e.g., Apple Pay)."

5. Risk Management

   • For "risks in electronic payment systems", list 4 risks + 1 mitigation (e.g., fraud → 3D Secure).

Final Note: Focus on how things work (not just definitions). Use diagrams for processes and tables for comparisons. In exams, always relate to Nepal (e.g., Khalti, NEPSE, Ncell).