secrity project keyvan

1

Security in Electronic Commerce

Keyvan vahidy

Graduate student

Collage nooretouba

Stno:8861097

1389

Security in e-commerce a subset of the overall security suite security issues surrounding the transfer, storage, data recovery

Security in e-commerce issues such as threats, risks facing

Network and Internetwork Security refer to measures needed to protect data during its transmission from one computer to another in a network or from one network to another in an internetwork.

abstract

Cryptography Principles of encryption, the encryption

Privacy Authenticity

Determines who canread the message

Determines who canwrite the message

• Prevent forgery• Prevent alteration

• Prevent eavesdropping• Prevent tracing

Goals of Cryptography

mechanismsCryptography

Mechanisms Cryptography types

Type Method Symmetric

Cryptography Symmetric Key to encrypt, decrypt equal

Method Symmetric two type:

Stream cipher

Block cipher

Type Method Symmetric

Block cipher

Stream cipher

Type Method Symmetric

Stream cipher a string of data to continuously receive the encrypted

Stream advantages: Diffusion Immunity insertations &

modifications Stream disadvantages.: Slow encryption

Error propagation

Type Method Symmetric

Block cipher Into every block of data to which the blocks are individually password

Block advantages: Speed of

transformation Low error propagation Block disadvantages.: Low diffusion

Malicious insertations & modifications possible

Encryption algorithms for security

AES

Two kinds of widely known Encryption algorithms : DES

Released by NBS in 1976, based on ‘Lucifer’

Combination of substitution and transposition

16 iterations with 56-bit key (64) Based on diffusion and confusion

(Shannon) Supported then adopted by NSA Can be broken (in 22 hours, parallel

attack) Key length dilemma, new algorithm to

be AES

Data Encryption Standard (DES)

Data Encryption Standard (DES)

Firstly the IP (explained below) is applied to the 64 bit plaintext. The result is then divided into two 32 bit halves, named L0 and R0. Then, the following happens 16 times:

Key transformation number i (a permutation, but dropping 8 bits off - defined in the specification) is applied to the key to produce 48 bits.

Apply the function f(Ri,Ki+1) (explained below) to produce a 32 bit output.

Exclusive OR Li and f(Ri,Ki+1), and call this Ri+1.

Make Li+1 = Ri

Data Encryption Standard (DES)

1978. By Rivest-Shamir-Adelman ) is a popular asymmetric key encryption standard.

Difficulty of determinating prime factors It is based on number theory (more

specifically the difficulty in factorizing a large number).

The key size ranges between 512 and 2048 bits.

It is used in many e-commerce applications such as the Secure Electronic Transaction (SET) protocol for credit card payment.

RSA Encryption

Picks two large prime numbers p and q

Multiplies p and q to obtain n Chooses d, such that d and

w=(p-1)(q-1) are relatively prime (no common factor).

Chooses e such that 1 = d x e mod w

Public key is: <e, n> Private key is: <d, n> Message code m, secret

code c c = me mod n m = cd mod n

RSA Encryption

Public Key

Only the decryption key is kept secret. The encryption key is made public.

Each user has two keys, one secret and one public. Public keys are maintained in a public directory. To send a message M to user B, encrypt using the

public key of B. B decrypts using his secret key. Signing Messages For a user Y to send a signed message M to user X. Y encrypts M using his secret key.

X decrypts the message using Y’s public key.

Public Key

Public Key Infrastructure(PKI)

A set of technologies and procedures to enable electronic authentication

Uses public key cryptography and digital certificates

Certificate life-cycle management

Many products from many vendors are available for certificate issuance and some management functions

Interoperability is a big issue -- especially when it comes to policies

Enabling the use of PKI in applications is limited today

Building and managing policies is the least understood issue

Public Key Infrastructure(PKI)

Public Key Infrastructure(PKI)

Authentication and registration of certificate applicants

System administration and access to signing keys

Application use and interfacing Trust between hierarchies Trust decisions to be made at different points

within the application need different views Certificate fields, authorization and allowed

use is really the hardest issue Authorization policies for management of CAs

and RAs

Public Key Infrastructure(PKI)

RA Zone

DMZ (DM Zone)

CA Zone

Internet

InternetApplications

CertificateRequest

Web Servers

CertificateDirectory

RAStations

CAStations

RA DB

Switchedsegment

StatusQuery

CertificateRequest

Store new certificate,CRL Update

CA DB

FIGURE 1: PKI SYSTEM BLOCK DIAGRAM[Numeric labels correspond to list above]

1 2 3

4

7

5

8

RAO Zone

RAO Stations(Operators at Consoles)

6

Basic idea (using symmetric key

encryption):•Suppose that the sender and receiver share a large random number (i.e. a secret).•The secret is attached to the message for finding the message digest.•The message (without the secret) together with the message digest is sent.

Message authentication code (MAC)

Viruses

Trojan h

computer worms

And,….

Malicious programs

Unauthorized software being run

Games Widely distributed

software Shareware Freeware Distributed software

Viruses

Trojan horse

A Trojan horse, or Trojan, is that appears to perform a desirable function for the user prior to run or install but instead facilitates unauthorized access of the user's computer system

a computer worm is a self-replicating. It uses a computer network to send copies of itself to other nodes (computers on the network) and it may do so without any user intervention. This is due to security shortcomings on the target computer. Unlike a virus, it does not need to attach itself to an existing program. Worms almost always cause at least some harm to the network, even if only by consuming bandwith, whereas viruses almost always corrupt or modify files on a targeted computer

computer worm

Firewalls

A firewall is a barrier placed between the private network and the outside world.

All incoming and outgoing traffic must pass through it.

Can be used to separate address domains. Control network traffic. Cost: ranges from no-cost (available on the

Internet) to $ 100,000 hardware/software system.

Types: Router-Based Host Based

Circuit Gateways

View of a Firewall

Use programmable routers

Control traffic based on IP

addresses or port

information.

Never allow in-

band programming via Telnet to a firewall router.

Firewall routers should never

advertise their

presence to

outside users.

Firewall Types(Router-Based)

Use a computer instead of router.

More flexible (ability to log all activities)

Works at application level

Use specialized software applications and service proxies.

Need specialized programs, only important services will be supported.

Firewall Types(Host-Based)

How to communicate securely:

SSL – “the web security protocols”

IPSEC – “the IP layer security protocol”

SMIME – “the email security protocol”

SET – “credit card transaction security protocol”

S-HTTP – “Secure Hypertext Transfer Protocol”

Others …

Secure Protocols

Negotiates and employs essential functions for secure transactions

Mutual Authentication Data Encryption Data Integrity

Operates between application and transport layers

SSL

HTTP NNTP

Web Applications

FTP TelnetFutureApps

Etc.

TCP/IP

SSL

Man in the middle

Spoofing attacks

Replay attacks and transaction freshness

Negotiation attacks

Snooping attacks

SSL and Security Attacks

Internet Protocol Security (IPsec) is a protocol suite for securing Internet Protocol (IP) communications by authenticating and encrypting each IP packet of a communication session. IPsec also includes protocols for establishing mutual authentication between agents at the beginning of the session and negotiation of cryptographic keys to be used during the session.

IPsec is an end-to-end security scheme operating in the Internet Layer of the Internet Protocol Suite. It can be used in protecting data flows between a pair of hosts (host-to-host), between a pair of security gateways (network-to-network),

IP SEC

S/MIME (Secure/Multipurpose Internet Mail Extensions) is a standard public key encryption and signing of mime data. S/MIME is on an IETF Standard Track and defined in a number of documents, most importantly RFCs. S/MIME was originally developed by RSA Data security Inc.

Change control to S/MIME has since been vested in the IETF and the specification is now layered on cryptography Message Syntax, an IETF specification that is identical in most respects with PKCS #7. S/MIME functionality is built into the majority of modern e-mail software and interoperates between them.

SMIME

SET standard two companies by VISA, Master card with the aim of ensuring security in the credit transaction year 1997 was introduced

Privacy information: credit card numbers of buyers see the seller remains hidden (using DES)

Cardholder authentication: digital signatures with certificates X.509v3

Authentication vendor: Digital signature certificate X.509v3

SET

Maintain confidentiality and purchase order payment information

Owner authentication Azaynrvkh cardholder authentication of a legitimate user is using a credit card account

Maintain the integrity of data transferred kidney

Ensure the safety of data transferred all Seller to provide authentication for the

transaction Ensure the best security techniques and

systems designed to protect all existing laws on electronic commerce transactions

Goal SET

Dual Signature(SET)

Security on application layer

Protection mechanism:

Digital Signature Message

authentication Message encryption Support private &

public key cryptograph Enhanced HTTP data

exchange

S-HTTP

Operate on application layer Encryption and digital signature Work only with (HTTP) Application dependant More secure than SSL at end point

even after data transfer No particular cryptographic system Multiple times encryption

S-HTTP

E-mail is the most widely used application in the Internet.

Who wants to read your mail ?

Business competitors Reporters,Criminals Friends and Family Two approaches are

used: PGP: Pretty Good Privacy PEM: Privacy-Enhanced

Mail

Electronic Mail Security

E-mail Security(PGP)

Available free worldwide in versions running on: DOS/Windows Unix Macintosh

Based on: RSA IDEA MD5

E-mail Security(PEM)

A draft Internet Standard (1993). Used with SMTP. Implemented at application layer. Provides:

Disclosure protection Originator authenticity Message integrity

Transaction Security

Card holder (Card

Holder): user

owns a credit card

Vendor (Mercha

nt): person

or organiza

tion intending

to sell their

goods through

the Internet

Card issuer

(Issuer): financial institutions such

as banks that

issue cards to

users and

does pay the user charge against him is buying

Agents participating in a Transaction

Agents participating in a Transaction

Financial Audit Institute (Acquirer): A financial institution required with the following tasks:

Open an Account for Sellers Ceiling set and enabled them credit cards Deposit amount received by the card vendor

account Payment Gateway (Payment Gateway):

processing messages and vendor payments by the Acquirer or the third person

Reference Certification (CA): X509 certificate issuer for cards owners, sellers, and payment gateway

Verify all certificates Decrypt the digital

license to obtain and decrypt the symmetric key block

Verify the sign vendor Decrypt digital pay to

obtain and decrypt the symmetric key block

Verify the signature block double payment

Requested and received permission Sender

Payment Gatway

Authorization response message

Related License Information

Recording information signs

Certificate

Customer Account

Order Buying(Customer)

Order Customer(Merchant)

Thank you for your attention dear