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Encryption Basics

Encryption Basics. Module 7 Section 2. History of Encryption. Secret - NSA National Security Agency has powerful computers - break codes monitors all communications between US and other countries and within Designs codes and breaks codes. History. 1970 - Developed by Diffie & Hellman

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Encryption Basics

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  1. Encryption Basics Module 7 Section 2

  2. History of Encryption • Secret - NSA • National Security Agency • has powerful computers - break codes • monitors all communications between US and other countries and within • Designs codes and breaks codes

  3. History • 1970 - Developed by Diffie & Hellman • Two mathematically related keys • to encrypt • to decrypt • Knowing the key to encrypt does not help decrypt • Each person has their own key pair

  4. History • The encrypting key can become public • Public key - encrypt • Private key - decrypt • Senders can ID the recipients public key to encrypt yet only the recipient can decrypt it. • No need to transfer secret keys

  5. Cryptography - Making and breaking of secret codes • Translation of the original message into a new incomprehensible one by a mathematical algorithm using a specific KEY • Plaintext - a message or data • Ciphertext - coded text • Decryption - decoding back to plaintext

  6. Encryption Includes: • Coding scheme or cryptographic algorithm • Specific sequence of characters key used by the algorithm

  7. Examples • Cereal box codes • Substitute cipher • Cryptoquip in newspaper

  8. Variations - Symmetric • Use the same key to encrypt and decrypt (secret key) • Requires a more secure system to send the key than the system itself

  9. Public Key Cryptography • Public Keys • Secret key for each pair of parties who wish to communicate privately • key is passed between the parties in a method more secure than the method used for sending the messages

  10. Variations - Asymmetric • Use a key (public key) to encrypt a message • Another (private key) to decrypt it • Requires both keys

  11. Reliability • The longer the key has remained unbroken, the stronger it is likely to be • The longer the key is in use, the more likely someone will be able to discover it • larger amount of info will be compromised • change key frequently

  12. Available Algorithms • DES – Data Encryption Standard • RSA algorithm • PGP – Pretty Good Privacy • IDEA – International Data Encryption Algorithm • Digital Signature

  13. DES - Data Encryption Standard • Developed by IBM • Adopted as a Federal Information Processing Standard • Uses a 56 bit key • Has been broken • To extend life - extend key to 128 bits • or triple DES

  14. RSA algorithm • Used in public key cryptography • Patented in US • Based on multiplication of large prime numbers

  15. PGP - Pretty Good Privacy • Based on RSA • Used for protecting E-Mail • Free • Distributed on Internet • Developed by Zimmerman for use with E-Mail

  16. IDEA - International Data Encryption Algorithm • 1991 in Switzerland • Uses 128 - bit key • More mathematical theory than DES

  17. Digital Signature • Add a statement of acceptance to the electronic document • encrypted with private key • cyphertext is decrypted with public key • providing any other key produced gibberish • Others can decrypt and read but only the one with the right key is signed

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