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Week Nine Assignment1). Using the Web or other resources, write a brief paper about RSA, its history, its methodology, and where it is used.2). Send a brief message (ten words minimum) using the Caesar Cypher.Required VideosVideo. John Oliver on This Week Tonight.Click HERE to watch or click embedded video below. easttom_ppt_08_final.ppt Unformatted Attachment Preview Computer Security Fundamentals by Chuck Easttom Chapter 8 Encryption Chapter 8 Objectives ◼ ◼ ◼ ◼ Explain the basics of encryption Discuss modern cryptography methods Select appropriate cryptography for your organization Understand the function and protocols of VPNs © 2016 Pearson, Inc. Chapter 8 Encryption 2 Introduction ◼ Encryption ❑ ❑ ❑ ◼ Scrambling information. One critical part to the security puzzle. Without it, all security measures are inadequate. Cryptography ❑ An art form © 2016 Pearson, Inc. Chapter 8 Encryption 3 Cryptography Basics ◼ Decryption ❑ ◼ Reversal of the scrambling protocol Encryption ❑ Algorithm scrambles plain Sender and receiver agree on algorithm ❑ Message difficult to re-create without protocol ❑ © 2016 Pearson, Inc. Chapter 8 Encryption 4 Cryptography Basics (cont.) ◼ Two basic types ◼ Single/symmetric key encryption ❑ ❑ ◼ Stream Block ▪ Substitution and transposition Public/asymmetric key encryption © 2016 Pearson, Inc. Chapter 8 Encryption 5 History of Encryption ◼ ◼ Old as written communication and war Caesar Cipher ❑ Shift cipher ◼ A DOG ❑ ❑ ❑ Shift 1 – B EPH Shift 2 – C FQI Shift negative 1 – Z CNF © 2016 Pearson, Inc. Chapter 8 Encryption 6 History of Encryption (cont.) ◼ Caesar Cipher ❑ ❑ Frequency distribution cracks this simple cipher. Substitution alphabet. ◼ ◼ Substitutes one letter in the alphabet for another. Caesar is a mono-alphabetic cipher. © 2016 Pearson, Inc. Chapter 8 Encryption 7 History of Encryption (cont.) ◼ ATBASH Rail Fence Vigenere ◼ Enigma ◼ ◼ © 2016 Pearson, Inc. Chapter 8 Encryption 8 History of Encryption (cont.) ◼ Multi-alphabetic ❑ Select multiple shifts ◼ ◼ ◼ ❑ Shift 1, 2, –1 Rotate through the shifts A DOG becomes B FNH Old cipher considered weak today © 2016 Pearson, Inc. Chapter 8 Encryption 9 Binary Operations ◼ Binary Operations ❑ ◼ AND, OR, XOR Example of AND operation 1 1 0 1 1 0 0 1 1 0 0 1 © 2016 Pearson, Inc. Chapter 8 Encryption 10 Binary Operations ◼ Example of OR operation 1 1 0 1 1 0 0 1 1 1 0 1 © 2016 Pearson, Inc. Chapter 8 Encryption 11 Binary Operations ◼ Example of XOR operation 1 1 0 1 1 0 0 1 0 1 0 0 © 2016 Pearson, Inc. Chapter 8 Encryption 12 Binary Operations ◼ XOR only reversible binary operation ❑ Convert plain text to ASCII A DOG = 065 032 068 079 071 ❑ Then, convert ASCII to binary 0100 0001, 0100 0100, 0100 1111, 0100 0111 © 2016 Pearson, Inc. Chapter 8 Encryption 13 Binary Operations ◼ XOR the ASCII 0100 0001, 0100 0100, 0100 1111, 0100 0111 1111 0111, 1111 0111, 1111 0111, 1111 0111 1011 0110, 1011 0011, 1011 1000, 1011 0000 ◼ Result is cipher text. © 2016 Pearson, Inc. Chapter 8 Encryption 14 Cryptography Terms ◼ ◼ ◼ ◼ Key: The bits that are combined with the plain text to encrypt it. In some cases this is random numbers; in other cases it is the result of some mathematical operation. Plain text: The unencrypted text. Cipher text: The encrypted text. Algorithm: A mathematical process for doing something. © 2016 Pearson, Inc. Chapter 8 Encryption 15 Modern Methods ◼ Single key (symmetric) encryption ❑ Same key to encrypt and decrypt ◼ Blowfish ❑ ❑ ❑ ❑ Symmetric block cipher Works on “blocks” of letters Uses variable length key (32–448 bits) Freeware © 2016 Pearson, Inc. Chapter 8 Encryption 16 Modern Methods (cont.) ◼ Data Encryption Standard (DES) 1. Divided into 64-bit blocks; then transposed 2. Manipulated by 16 steps of encryption, using 56-bit key 3. Scrambled by a swapping algorithm 4. Transposed one final time © 2016 Pearson, Inc. Chapter 8 Encryption 17 Modern Methods (cont.) ◼ ◼ Advanced Encryption Standard (AES). Advanced Encryption Standard was the algorithm eventually chosen to replace DES. It is a block cipher that works on 128bit blocks. It can have one of three key sizes of 128, 192, or 256 bits. This was selected by the United States government to be the replacement for DES and is now the most widely used symmetric key algorithm. © 2016 Pearson, Inc. Chapter 8 Encryption 18 Modern Methods (cont.) ◼ One major problem with symmetric key encryption How do you transmit the symmetric key? ◼ The answer: public key encryption © 2016 Pearson, Inc. Chapter 8 Encryption 19 Modern Methods (cont.) ◼ Public key (asymmetric) encryption ❑ ❑ ❑ ❑ Opposite of single key encryption. One key (public key) used to encrypt . One key (private key) used to decrypt. Only holder of a private key can decrypt messages. © 2016 Pearson, Inc. Chapter 8 Encryption 20 Modern Methods (cont.) ◼ Public key (asymmetric) encryption ❑ ❑ ❑ Depends on large prime numbers, factoring, and number theory. Public key encryption is most widely used. Pretty Good Privacy (PGP): ◼ ◼ Freeware Quite secure © 2016 Pearson, Inc. Chapter 8 Encryption 21 Modern Methods (cont.) ◼ Public key (asymmetric) encryption ❑ Pretty Good Privacy (PGP) ◼ ◼ ◼ Freeware Phil Zimmerman – 2004 Quite secure © 2016 Pearson, Inc. Chapter 8 Encryption 22 Modern Methods (cont.) The MIT Distribution Center for PGP home page (http://web.mit.edu/network/pgp.html) © 2016 Pearson, Inc. Chapter 8 Encryption 23 Modern Methods (cont.) ◼ Public key (asymmetric) encryption ❑ RSA ◼ ◼ ◼ ◼ You start by generating two large random primes, p and q, of approximately equal size. Now you need to pick two numbers so that when multiplied together the product will be the size you want (that is, 128 bits, 256 bits, and so on). Now multiply p and q to get n. Let n = pq Let m = (p - 1)(q – 1) © 2016 Pearson, Inc. Chapter 8 Encryption 24 Modern Methods (cont.) ◼ Public key (asymmetric) encryption ❑ RSA ◼ ◼ ◼ ◼ ◼ Now select another number; call this number e. Pick e so that it is co-prime to m. Choose a small number e, co-prime to m. Youare almost done generating a key. Now you just find a number d that when multiplied by e and modulo m would yield a 1. (Note: Modulo means to divide two numbers and return the remainder. For example 8 modulo 3 would be 2.). Find d, such that de \% m = 1. Now publish e and n as the public key. Keep d and n as the secret key. To encrypt, simply take your message raised to the e power and modulo n. © 2016 Pearson, Inc. Chapter 8 Encryption 25 Modern Methods (cont.) The RSA Security home page (http://www.rsasecurity.com) © 2016 Pearson, Inc. Chapter 8 Encryption 26 Modern Methods (cont.) ◼ Legitimate versus fraudulent encryption ❑ Warning signs of frauds ◼ ◼ ◼ Unbreakable Certified Inexperienced people © 2016 Pearson, Inc. Chapter 8 Encryption 27 Avoid ‘bad’ crypto ◼ ◼ ◼ ◼ Unbreakable Unhackable Secret algorithm Kerhoff’s principle © 2016 Pearson, Inc. Chapter 8 Encryption 28 Digital Signatures ◼ A digital signature is not used to ensure the confidentiality of a message, but rather to guarantee who sent the message. This is referred to as nonrepudiation. Essentially, it proves who the sender is. Digital signatures are actually rather simple, but clever. They simply reverse the asymmetric encryption process. Recall that in asymmetric encryption the public key (which anyone can have access to) is used to encrypt a message to the recipient, and the private key (which is kept secure and private) can decrypt it. With a digital signature, the sender encrypts something with his private key. If the recipient can decrypt that with the senders public key, then it must have been sent by the person purported to have sent the message. © 2016 Pearson, Inc. Chapter 8 Encryption 29 Hash ◼ Hashing is a type of cryptographic algorithm that has some specific characteristics. First and foremost it is one way. That means you cannot unhash something. The second characteristic is that you get a fixed-length output no matter what input is given. Finally, it should have few or no collisions. A collision is when two different inputs provide the same output. © 2016 Pearson, Inc. Chapter 8 Encryption 30 Hash – cont. ◼ ◼ ◼ ◼ MD5 SHA1 SHA2 SHA3 © 2016 Pearson, Inc. Chapter 8 Encryption 31 3 2 VERY Simple Illustration of Rainbow Tables Password MD5 Hash (in Hex) Password MD5 Hash (in Hex) aaaa 74b87337454200d4d33 f80c4663dc5e5 aaaaa 594f803b380a41396ed 63dca39503542 aaab 4c189b020ceb022e0ec c42482802e2b8 aaabb 120858a7016efcfab669 67b834e9153c aaac 3963a2ba65ac8eb1c6e 2140460031925 aaacc ee43671d755ac457cfe 6e32d1894788e aaa1 39dc4f1ee693e5adabd dd872247e451f aaa1a 5bbac29650eb36b4de1 6885c190a9fa3 aaa2 0ad346c93c16e85e2cb 117ff1fcfada3 aaa2a 597f0ce6d11567cc691b 3f5df35594cb aaa4 ee93fca7c150d9c548af f721c87d0986 aaa4a 4305dc076b3ba2bf8d5 5524cddf5a72d © 2016 Pearson, Inc. Chapter 8 Encryption 3 3 Hash - Salt  Random bits added to further secure encryption or hashing. Most often encountered with hashing, to prevent Rainbow Table attacks. ◼ Essentially the salt is intermixed with the message that is to be hashed. Consider this example. You have a password that is pass001 in binary that is 01110000 01100001 01110011 01110011 00110000 00110000 00110001 A salt algorithm would insert bits periodically, lets assume for our example that we insert bits every 4th bit giving us 0111100001 0110100011 0111100111 0111100111 0011100001 0011100001 0011100011 If you convert that to text you would get xZ7�� # ◼ ◼ ◼ ◼ ◼ ◼ ◼ © 2016 Pearson, Inc. Chapter 8 Encryption Historical Steganography ◼ ◼ ◼ The ancient Chinese wrapped notes in wax and swallowed them for transport. In ancient Greece a messenger’s head might be shaved, a message written on his head, then his hair was allowed to grow back. In 1518 Johannes Trithmeus wrote a book on cryptography and described a technique where a message was hidden by having each letter taken as a word from a specific column. © 2016 Pearson, Inc. Chapter 8 Encryption Historical Steganography Continued ◼ ◼ During WW II the French Resistance sent messages written on the backs of couriers using invisible ink Microdots are images/undeveloped film the size of a typewriter period, embedded on an innocuous documents. These were said to be used by spys during the Cold War. © 2016 Pearson, Inc. Chapter 8 Encryption Steganography Terms ◼ ◼ ◼ Payload is the data to be covertly communicated. The carrier is the signal, stream, or data file into which the payload is hidden. This is also sometimes called the cover object. The channel is the type of medium used. © 2016 Pearson, Inc. Chapter 8 Encryption 3 7 Cryptanalysis ◼ ◼ ◼ ◼ Ciphertext Only Attack Known plain text Chosen plain text Related Key © 2016 Pearson, Inc. Chapter 8 Encryption Summary ◼ ◼ Encryption is a basic element of security. Encrypting data when transmitting is an integral part of any security plan. © 2016 Pearson, Inc. Chapter 8 Encryption 38 ... 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