Security

Security and Authentication Daniel L. Silver, Ph.D. Acadia & Dalhousie Univs.

Objectives To introduce the basics E-Commerce security issues and web entity authentication

Outline Why is security such an issue? Physical security IT Security Basics – Firewalls Public Key Cryptography SSL – Secure Socket Layer SET – Secure Electronic Transactions

Why is Security an Issue? The Internet lets you travel outside of your network and others travel in – Those travelers are not all friendly! Critical and private information can be snooped — sniffed Information can be deleted or destroyed The Internet provides an opportunity for anonymous and rapid theft of lots of money

How many categories/classes of security invasions/breaches can you find? User/password – shoulder surfing Trojan horses Password breaking (various strategies) Denial of service attacks – flood the server with requests Packet sniffing on net (wire tap, wireless recon.) Spoofing websites Dumpster diving – garbage search

How many categories/classes of security invasions/breaches can you find? Hacking user IDs and passwords Denial of service/access Physical invasion of a data centre Social Engineering – exploit human good nature to get info you should not have Internet Packet Sniffing Taking advantage of known frailties in systems Domain Hijacking – impersonating another legitimate domain Buffer Overflows Viruses Attacks by employees

Components of Security Diagram by Konstantin Beznosov

Five Major Requirements of a Secure Transaction Privacy – how to ensure information has not been captured by a third party Integrity – how to ensure the information has not been altered in transit Authentication – how to ensure the identity of the sender and receiver Authorization – how to ensure a user has the authority to access / update information Non-repudiation – how do you legally prove that a message was sent or received

Physical Security Large mainframe systems have always had adequate physical security The transition from LAN to WAN to Internet has caused new interest in these methods Physical security means locked doors and security personnel Options are to host on a secure ISP/ASP ( InternetHosting .com )

IT Security Basics Avoidance – preventing a security breach Using a firewall system to frontend your intranet (or LAN) to the Internet Minimization – early warning signals and action plans so as to reduce exposure Attempted to access secure directories Recovery - regular backups should be made and recovery periodically tested

Using a Firewall A firewall server or router acts as an electronic security cop No machine other than firewall is directly accessible from Internet May also function as a “proxy” server allowing intranet systems to access only portions of the Internet Internet security methods are focused at the firewall reducing cost and admin overhead

Security through HTTPS Browser Client 1 Server A HTTP TCP/IP HTTP Server App. Server Fire Wall Server Server C Server B

IT Security Basics Passwords (and potentially User Ids) should be forced to change periodically Passwords should be difficult to guess Try to create passwords such as: To Be or Not To Be  2bon2b Databases should be secured in terms of access rights to data (usually by individual or group)

IT Security Basics Software, particularly low layer components such as the operating system and DBMS, should be kept to recent patch levels Access from dial-in lines should be limited and if possible call-back systems can be used

Cryptography Cryptography or ciphering is an ancient method of encoding a message — only a receiver with a key can decipher the content A single (symmetric) secret key is used to encrypt and decrypt Requires the communication of the key between sender and receiver! Basis of nuclear war-head command and control security

14-15-17-12 12-14-1-14-9-25-9-2-14 17-12 11-1-23-12-9

Public Key Cryptography In 1976 Diffie & Hellman at Stanford U. developed public-key cryptography Asymmetric: Private key – kept secret by owner Public key – distributed freely to all who wish to send Generated by computer algorithm, so a mathematical relation exists between them ... however ... It is computationally difficult to determine the private key from the public key, even with knowledge of the encryption algorithm

Public Key Cryptography The keys come in the form of tightly coupled pairs which anyone can generate using methods such as RSA, SHA-1, DSA (RSA is most common) Javascript demo: http://shop-js.sourceforge.net/crypto2.htm There is only one public key corresponding to any one private key and vice versa Sender encodes data using public key of receiver Receiver decodes data using unique private key, no one else can do the same This ensures integrity of the data

Authentication How can you be sure that the person sending the encrypted data is who they say they are This requires some method of authenticating the identity of the sender The solution is for the sender to “sign” the data using his/her private key – the data is encrypted using the sender’s private key The receiver validates (decrypts the data) the “signature” using the sender’s public key This will work as long as receiver can be sure the sender’s public key belongs to the sender and not an imposter … enter PKI

Integrity and Authentication Example: Consider a merchant wants to send a secure message to a customer: Merchant encrypts message using customer’s public key Merchant then signs message by encrypting with their private key Customer decrypts using the merchants public key to prove authenticity of sender Customer decrypts using their private key to ensure integrity of message

PKI – Public Key Infrastructure Integrates PK cryptography with digital certificates and certificate authorities (CA) Digital certificate = issued by a CA, includes user name, public key, serial number, expiration date, signature of trusted CA (message encrypted by CA’s private key) Receipt of a valid certificate is proof of identity – can be checked at CAs sight www.verisign.com is major player

Model for Network Security Information Channel Message Secret Information Message Secret Information Sender Receiver Trusted Third Party Authentication or Certificate Authority Opponent

Security and HTTPS Certificate is an entity’s public key plus other identification (name, CA signature) SSL – Secure Socket Layer Lies between TCP/IP and HTTP and performs encryption HTTPS is the HTTP protocol that employs SSL – it uses a separate server port (default = 443)

Security through HTTPS Browser Database Server Client 1 Server A URL HTTP TCP/IP HTTP Server App. Server index.html Bank Server Dedicated prog.jsp HTTPS port = 80 port = 443

SSL – Secure Socket Layer Client makes HTTPS connection to server Server sends back SSL version and certificate Client checks if certificate from CA Client creates session “premaster secret”, encrypts it and sends it to server and creates “master secret” Server uses its private key to decrypt “premaster secret” and create the same “master secret” The master secret is used by both to create session keys for encryption and decryption

SET – Secure Electronic Transfer Developed by Visa & Mastercard Designed to protect E-Comm transactions SET uses digital certificates to authenticate customer, merchant and financial institution Merchants must have digital certificate and special SET software Customers must have digital certificate and SET e-Wallet software

Major Architectural Components of the Web Internet Browser Database Server Client 1 Server A Server B Bank Server URL HTTP TCP/IP Browser Client 2 HTTP Server App. Server index.html Bank Server prog.jsp

Resources / References RSA demos: http://cisnet.baruch.cuny.edu/holowczak/classes/9444/rsademo/ http://islab.oregonstate.edu/koc/ece575/02Project/Mor/

Security

More Related Content

What's hot (19)

Viewers also liked (20)

Similar to Security (20)

Recently uploaded (20)

Security