The document discusses electronic payment systems, their objectives, examples, types, and security services. It describes methods like e-cash, smart cards, and credit/debit cards. E-cash uses cryptographic algorithms to prevent double spending while preserving anonymity. Smart cards can process data and payments. Credit cards require repayment of spent amounts. Payment gateways protect credit card details and ensure secure transactions between customers, merchants and processors. The conclusion states that electronic payment systems have expanded markets and made payments more convenient.