Notes on Chapter 3: Security through authentication and encryption

Explain encryption methods and how they are used

Describe authentication methods and how they are used

Explain and configure IP security

Discuss attacks on encryption and authentication methods

Sniffers: software to capture information sent across a network; often gain access to account then install

(differentiate between legitimate sniffing for network analysis and troubleshooting traffic flow)

Encryption: disguise data to make it unintelligible except for intended recipients

Cryptography: coding messages

Enigma vs. Colossus

Coding

Ciphers code either each bit, or a block, of data

Keys and algorithm (recipe);

secret key uses same key (symmetrical) to encrypting and decrypting;
public key uses both a public and private key, (asymmetric) one to encrypt and one to decrypt PGP

Hashing SSNàStudent ID (must verify uniqueness)

MD5 in SNMP rehashes 4 times

Checking the validity of data

Checksum

Windows

MPPE RAS over PPP or VPN and PPTP

            VPN telephone analogy

Encrypting file system sits on NTFS, uses Public Key

            Cipher command (Cipher /?)

Linux

CFS Cryptographic File System on ext2 and ext3

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Authentication Methods

Session Authentication encrypt sequence to foil sniffers

Digital Certificates (X.509)

Kerberos

SSL

SSH

	Single computer	LAN	IP
basic		Challenge and Response	Transmission Layer-weak
better	challenge and response	Kerberos	SSL
	log in for adm rights	tickets, and time limits	browser and server agree
best	Security Token	EAP	SSH
	Thumb scan or smart card	valid phone or IP	log in

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Attacks on encryption and authentication

Brute force

Steal password

Guess password

Weak keys 56 bit vs PGP and strong key
“How difficult? Given all of today's computing power and available time — even a billion computers doing a billion checks a second — it is not possible to decipher the result of strong cryptography before the end of the universe.”

Toward lab 3: Questions and 3.7