1. Electronic Payments E-payment methods –Credit cards –Electronic funds transfer (EFT) –E-payments Smart cards Digital cash and script Digital checks E-billing –All have the ability to transfer payment from one person or party to another

2. Electronic Payments (cont.) Four parts involved in e- payments –Issuer –Customer/payer/buyer –Merchant/payee/seller –Regulator Key issue of trust must be addressed –Privacy –Authentication and authorization –Integrity –Nonrepudiation

3. Electronic Payments (cont.) –Independence –Interoperability and portability –Security –Anonymity –Divisibility –Ease of use –Transaction fees Crucial factors in determining which method of e-payment achieves widespread acceptance

4. Security for E-Payments Public key infrastructure  PlaintextEncryption algorithm  CiphertextKey Types of encryption systems  Symmetric (private key) Used to encrypt and decrypt plain text Shared by sender and receiver of text  Asymmetric (public key) Uses a pair of keys Public key to encrypt the message Private key to decrypt the message

5. Private Key Encryption

6. Public Key Encryption Size of key RSA algorithm Speed of Key Rijndael algorithm

7. Digital Signatures: authenticity and nondenial –Analogous to handwritten signature –Based on public keys –Used to: Authenticate the identity of the sender of a message or document Ensure the original content of the electronic message or document is unchanged Security for E-Payments (cont.)

8. Digital Signatures: authenticity and nondenial (cont.) –Benefits : Portable Cannot be easily repudiated or imitated Can be time stamped

9. Digital Signatures

10. Security for E-Payments (cont.) Digital certificates –Identifying the holder of a public key (Key- Exchange) –Issued by a trusted certificate authority (CA) Name : “Richard” key-Exchange Key : Signature Key : Serial # : 29483756 Other Data : 10236283025273 Expires : 6/18/04 Signed : CA’s Signature

11. Security for E-Payments (cont.) Secure socket layer/transport layer security –Secure socket layer (SLL) — handle on Web browser, utilizing CAs and data encryption Encryption Digital certificates Digital signatures –In 1996 SSL was standardized and named transport layer security (TSL) –Operates at TCP/IP layer (base layer for Internet) –IPSec — secure version of IP protocol

12. SET Vs. SSL Secure Electronic Transaction (SET) Secure Socket Layer (SSL) ComplexSimple SET—tailored to credit card payment to merchants SSL—protocol for general- purpose secure message exchanges (encryption) SET protocol hides customer’s credit card information from merchants and order information to banks, to protect privacy (dual signature) SSL protocol may use a certificate, but there is no payment gateway. Merchants need to receive ordering information and credit card information (capturing process initiated by merchants)