Introduction to CryptographyIntroduction to CryptographyDr. Nazli HardyFlow 3 parts to Cryptography lecture in CSCI 415 Intro to Cryptography  Symmetric Key Encryption  Asymmetric Key Encryption (digital signatures/ digital certificates/ digital envelopes) SSL/ TLS 3 related lab componentsIntroduction to CryptographyIntroduction to CryptographyDr. Nazli HardyOverview The fundamentals and history Character-Level Encryption Substitutional• Monoalphabetic• Polyalphabetic– Gronsfeld’s System– Vigenere Transpositional Bit-Level Encryption Permutation Exclusive OR (XOR) Rotation Data Encryption Standard (DES) Advanced Encryption Standard (AES) International Data Encryption Algorithm, Blowfish and RC5 (block ciphers)Introduction to CryptographyIntroduction to CryptographyDr. Nazli HardyFundamentals Cryptography: process of converting plaintext (readable text) into ciphertext(unreadable/ encrypted text) by authorized sender - encryption Equally important is this system is the re-conversion from unreadable to readable text by authorized recipient – decryption Keys Symmetric Encryption Asymmetric encryption While cryptography obscures/ hides the meaning of the data from unauthorized user, it does not hide the data itself (what is that process called?)Introduction to CryptographyIntroduction to CryptographyDr. Nazli HardyHistory – cryptography is nothing new Egyptian hieroglyphics found on ancient monuments were encrypted (ca. 4500 BC) The Book of Jeremiah was written using a cipher, or key, known as atbash Connected with religious and academic literature and powers of the day (Queen Elizabeth I ca. 1550) Kama Sutra (ca. 2000 years ago) recommends that men and women learn the art of cryptography Julius Caesar: shifter letters by 3 positions (i.e. ‘a’ becomes ‘d’) Used both in WW I and WW II Good book: “The Codebreakers”, David Kahn (McMillan, 1967)Introduction to CryptographyIntroduction to CryptographyDr. Nazli HardyWar Machines Enigma machines used by Germans during WW II Developed by Arthur Scherbius How does it work?The code was first broken by Polish cryptographers, then by the British and AmericansIntroduction to CryptographyIntroduction to CryptographyDr. Nazli HardyEnigmaDisplayed at the National Cryptologic Museum1) Commercial Enigma2) Enigma T3) Enigma G4) Unidentified5) Luftwaffe (Air Force) Enigma6) Heer (Army) Enigma7) Kriegsmarine (Naval) Enigma — M4.Introduction to CryptographyIntroduction to CryptographyDr. Nazli HardySymmetric and Asymmetric Cryptography AlgorithmsAlgorithm used for verificationTakes a variable-length input and converts it to a fixed-length output strong called a hash-valueHashing Uses 2 keys; one to encrypt and one to decrypt data Support authentication and nonrepudiation Slower than symmetric algorithms Known as public key cryptographyAsymmetric Uses a single key to encrypt and decrypt data Both sender and receiver must agree on the key before the data is transmitted Support confidentiality, but not authentication and nonrepudiation Faster than asymmetric algorithms Some difficulties??SymmetricDescriptionType of AlgorithmArticle: http://www.wired.com/news/technology/0,1282,32263,00.htmlIntroduction to CryptographyIntroduction to CryptographyDr. Nazli HardyCharacter-Level Encryption – Substitutional - Monoalphabetic Caesar’s CipherIntroduction to CryptographyIntroduction to CryptographyDr. Nazli HardyCharacter-Level Encryption – Substitutional - Polyalphabetic Gronsfeld’s SystemCrypto:DLEFSNORGText:714371437Key:XTPLHD1WSOKGC4ZVRNJFB3YUQMIEA7Writing the letters out, row by row, and starting with the row having the lowest keyfigure gives the following unordered sequence: DHLPTXBFJNRVZCGKOSWAEIMQUYCrypto:DLEFSNORGText:714371437Key:more secureIntroduction to CryptographyIntroduction to CryptographyDr. Nazli HardyCharacter-Level Encryption – Substitutional - Standard VigenereVigenere Table ABCDEFGHIJKLMNOPQRSTUVWXYZ BCDEFGHIJKLMNOPQRSTUVWXYZA CDEFGHIJKLMNOPQRSTUVWXYZAB DEFGHIJKLMNOPQRSTUVWXYZABC EFGHIJKLMNOPQRSTUVWXYZABCD FGHIJKLMNOPQRSTUVWXYZABCDE GHIJKLMNOPQRSTUVWXYZABCDEF HIJKLMNOPQRSTUVWXYZABCDEFG IJKLMNOPQRSTUVWXYZABCDEFGH JKLMNOPQRSTUVWXYZABCDEFGHI KLMNOPQRSTUVWXYZABCDEFGHIJ LMNOPQRSTUVWXYZABCDEFGHIJK MNOPQRSTUVWXYZABCDEFGHIJKL NOPQRSTUVWXYZABCDEFGHIJKLM OPQRSTUVWXYZABCDEFGHIJKLMN PQRSTUVWXYZABCDEFGHIJKLMNO QRSTUVWXYZABCDEFGHIJKLMNOP RSTUVWXYZABCDEFGHIJKLMNOPQ STUVWXYZABCDEFGHIJKLMNOPQR TUVWXYZABCDEFGHIJKLMNOPQRS UVWXYZABCDEFGHIJKLMNOPQRST VWXYZABCDEFGHIJKLMNOPQRSTU WXYZABCDEFGHIJKLMNOPQRSTUV XYZABCDEFGHIJKLMNOPQRSTUVW YZABCDEFGHIJKLMNOPQRSTUVWX ZABCDEFGHIJKLMNOPQRSTUVWXY PlaintextKey LetterTHIGRIUNYCESYTIRUCESTDIMTAKCATTAPlaintextKey LetterYTIRUCESYTIRUCESHGINXTDIMTAKCATTAPlaintextKey LetterCryptoIntroduction to CryptographyIntroduction to CryptographyDr. Nazli HardyCharacter-Level Encryption – Substitutional -Vigenere Standard Vigenere was the main cryptographic system used by the Confederated States during the American Civil War, and four of the keyphrases used by the Confederates were:  IN GOD WE TRUST COMPLETE VICTORY MANCHESTER BLUFF COME RETRIBUTIONThe History of Codes and Ciphers in the United States prior to World War IIntroduction to CryptographyIntroduction to CryptographyDr. Nazli HardyCharacter-Level Encryption – Substitutional - Unordered VigenereA table using a body consisting of a mixed sequence based on the keyword SPHINX could look like this  SPHINXABCDEFGJKLMOQRTUVWYZ PHINXABCDEFGJKLMOQRTUVWYZS HINXABCDEFGJKLMOQRTUVWYZSP INXABCDEFGJKLMOQRTUVWYZSPH NXABCDEFGJKLMOQRTUVWYZSPHI XABCDEFGJKLMOQRTUVWYZSPHIN ABCDEFGJKLMOQRTUVWYZSPHINX BCDEFGJKLMOQRTUVWYZSPHINXA CDEFGJKLMOQRTUVWYZSPHINXAB DEFGJKLMOQRTUVWYZSPHINXABC EFGJKLMOQRTUVWYZSPHINXABCD FGJKLMOQRTUVWYZSPHINXABCDE GJKLMOQRTUVWYZSPHINXABCDEF JKLMOQRTUVWYZSPHINXABCDEFG KLMOQRTUVWYZSPHINXABCDEFGJ LMOQRTUVWYZSPHINXABCDEFGJK MOQRTUVWYZSPHINXABCDEFGJKL OQRTUVWYZSPHINXABCDEFGJKLM QRTUVWYZSPHINXABCDEFGJKLMO RTUVWYZSPHINXABCDEFGJKLMOQ TUVWYZSPHINXABCDEFGJKLMOQR UVWYZSPHINXABCDEFGJKLMOQRT VWYZSPHINXABCDEFGJKLMOQRTU WYZSPHINXABCDEFGJKLMOQRTUV YZSPHINXABCDEFGJKLMOQRTUVW ZSPHINXABCDEFGJKLMOQRTUVWY PlaintextKey LetterTHIGRIUNYCESYTIRUCESTDIMTAKCATTAPlaintextKey LetterYTIRUCESYTIRUCESHGINNTDIMTAKCATTAPlaintextKey LetterCryptoIntroduction to CryptographyIntroduction to CryptographyDr. Nazli