J.W. Ryder Basic Internet Security Concepts J.W. Ryder

J.W. Ryder Introduction The internet is a vast wilderness, an infinite world of opportunity Exploring, , free software, chat, video, e- business, information, games Explored by humans

J.W. Ryder Internet Security Concepts Introduction of several basic security concepts General mechanisms for protection

J.W. Ryder Sniffing and Spoofing [1] Sniffing –The ability to inspect IP Datagrams which are not destined for the current host. Spoofing –After sniffing, create malicious havoc on the internet

J.W. Ryder Unprotected Internet node Private Network node Secure Gateway node A Guy Gabrielle Poirot (C) Sears Bank (I) A Guy’s Swiss Bank Wall Street (N) Steve Burns (C) Ramon Sanchez (A) 1

J.W. Ryder A Guy has no integrity Swiss Bank Scam Integrity - The guarantee that, upon receipt of a datagram from the network, the receiver will be able to determine if the data was changed in transit

J.W. Ryder Ramon springs for sound Sears solid state stereos Authentication - The guarantee that, upon receipt of a datagram from the network, the receiver will be able to determine if the stated sender of the datagram is, in fact, the sender

J.W. Ryder A guy sniffs success Gabrielle and Steve almost strike it rich Confidentiality - Ensure that each party, which is supposed to see the data, sees the data and ensure that those who should not see the data, never see the data.

J.W. Ryder Wall Street Woes A guy spots a hot stock tip Non-repudiation - Once a host has sent a datagram, ensure that that same host cannot later claim that they did not send the datagram

J.W. Ryder A guy becomes desperate Bring Wall St. to its knees Denial of Service Attack - Flood a given IP Address (Host) with packets so that it spends the majority of its processing time denying service

J.W. Ryder Physical Adapter IP In Comm. Stack One Way Hash Functions (MD5, SHA1) Crypto Functions (DES, CDMF, 3DES) Key Mgmt. Functions Application 2

J.W. Ryder Protocol Flow [2, 3] Through layers, each layer has a collection of responsibilities ISO OSI Reference Model - (Open Systems Interconnection) IP Datagram

J.W. Ryder IP Hdr.Data IP Datagram DataMAC FnDigest MAC Function IP Hdr.DataDigest Integrity 3

J.W. Ryder Keys Bit values fed into cryptographic algorithms and one way hashing functions which provide help provide confidentiality, integrity, and authentication The longer the better - 40, 48, 56, 128 Brute force attacks can win with small keys

J.W. Ryder Symmetric Keys Have qualities such as life times, refresh rates, etc. Symmetric - Keys that are shared secrets on N cooperating, trusted hosts

J.W. Ryder Asymmetric Public / Private key pairs Public key lists kept on well known public key servers Public key is no secret. If it is, the strategy will not work. Public and Private keys inverse functional values Private key is only known to you and must remain secret

J.W. Ryder Concept Sender encrypts data with private key Receiver decrypts data with public key Receiver replies after encrypting with public key Sender receives response and decrypts with private key

J.W. Ryder Data Encryption Function IP Hdr. Key Crypto Fn.Encrypted Data Encrypted Data Confidentiality 4

J.W. Ryder Decryption Function Data Key Crypto Fn. Encrypted Data Confidentiality Data 5

J.W. Ryder MACs Message Authentication Codes, One Way Hashing Functions A function, easy to compute but computationally infeasible to find 2 messages M1 and M2 such that – h (M1) = h (M2) MD5 (Rivest, Shamir, Adleman) RSA ; SHA1 (NIST) MD5 yields a 128 bit digest [3]

J.W. Ryder DES Data Encryption Standard U.S. Govt. Standard 56 bit key - originally 128 bits Absolute elimination of exhaustive search of key space U.S. Security Agency Request - Reduce to 56 bits Export CDMF (40 bits) Keys are secrets to algorithms, not algorithms themselves [4, 5]

J.W. Ryder IP Hdr. Encrypted Data Confidentiality, Integrity, & Authentication IP Hdr. Encrypted Data Digest Digital Signature (Enc. Digest) Confidentiality & Integrity

J.W. Ryder DataEM Key MAC CF DS Digest Keyed Digest MAC_Time < CF _Time Why would a guy prefer a Digital Signature over a Keyed Digest ? Why not? What types of Security are provided with EM, DS, Digest, Keyed Digest?

J.W. Ryder Msg EM Msg MD DS KD No Security Integrity Confidentiality Conf. & Integrity Integrity & Auth. Conf., Int., & Auth. Integrity & Auth. Conf., Int., & Auth.

J.W. Ryder Purpose Some ideas on Internet Security Classes of mischief on Internet, definitions Tools to fight mischief Combinations of these tools

J.W. Ryder Purpose continued Very high level Good starting point for further study about General networking & strategies Cryptography Key Management Algorithm Analysis

J.W. Ryder Post Presentation Results Should be familiar with concepts & terms such as –Integrity, Authentication, Non- repudiation, Confidentiality –Keys, MACs, Cryptography, Digest, Digital Certificates, Datagram –High level understanding of some methods to combat some the above types of Internet mischief