Encryption

• symmetric encryption is when the same key is used to encrypt and decrypt the message
• asymmetric encryption uses two keys, one public and one private
• a hash function takes a variable length input and produces a fixed-length output called a digest or hash value
• the strength of hashing lies in its irreversibility - there is no way to reverse engineer the original data from the hash value
• the vernam cypher:

  • Has a one time pad
  • Must be transferred in person
  • Uses XOR mask
• Brute force attack 

   

  • A brute force attack attempts to apply every possible key to decrypt ciphertext 
• Hashing

   

  • A hashing function provides a mapping between arbitrary length Input and a usually fixed length or smaller output 

   

  • It is one-way; you cannot get back to the original

   

  • This is useful for storing encrypted pins and passwords so that they cannot be read by a hacker 
  • To verify a users password the software applies the hash function to the user input and compares the hashed result with the one stored